Now I have done all the experiments. Firstly, the cleaning agents are not as important as the cleaning tool. You do have to get one of the carpet "steamers" - not hot steam but will apply shampoo on the carpet and then suck it up. Without it you have to soak the wet dirt up with a micro fibre or just cloth. For removing stain in a small area it's perfectly OK. It's just don't worth the manual labour if you can get a cheap steamer for smaller areas.
Now the cleaning agents. Of course baking soda. First you optionally spread baking soda around the carpet, more on dirty areas and stains. You just drop a scoop in mid air and it will spread pretty evenly when the powder hit the ground.
Now spray the dirty area and stains with white vinegar, neat or diluted. It depends on how dirty your carpet is and how much you want to spend on vinegar. It's cheap but still a couple of dollars per gallon. The chemical will produce an acid temporary for extra cleaning. The resulting neutralized salt is slightly yellowish. It doesn't stain but if you have pure white carpet, I would try in a small area first.
Now the ingredient for carpet shampoo. Add a cup of vinegar to it, more or less if you want. Optionally add a cup of rubbing alcohol to it. Optionally you need a little bubble, if only you need it to see how much dirty water is being sucked back into the steamer. You can mix with carpet shampoo, but test first if there is adverse or mutual suppressing reactions. You can add an oz or two of laundry detergent. Or, I have an ultimately biodegradable car shampoo with very low suds.
Then follow the steamer instructions to clean the carpet. Put it simply, for the first pass backwards, press the button to apply "shampoo". Then at least pass a few times along the same area to suck back up all the shampoo. Don't reapply shampoo unless you suck up all the shampoo that can be sucked up. If the carpet get too wet, it will affect all the glue in all the layers. The carpet may get loose or be damaged.
You can replace the steamer by hand. But when I dispose of the used shampoo bucket, I always have a dark grey bucket of dirty water. The dirty water is still very dirty even if I wash in consecutive days. So that's the power of the steamer.
One thing to watch is that the baking soda from the carpet can "clog" the dirty water circulation. If that happens you just need to rinse the dirty bucket in warm or cold water. Baking soda is soluble in water. For this clogging reason I don't use baking soda as shampoo. But I think you can, but then don't add vinegar to neutralize it.
I had a Hover steamer, the biggest I could get. It was a mistake. It's so heavy to lift upstairs. Yes you can separate the buckets from the steamer before lifting but that's extra work. Even the to and fro action need some muscle if you go over the whole house.
My steamer clogged long ago, with fibre and dirt from the carpets. It it also leaks from the tool tube. I cleaned it up, took it apart, and realized that the clog can easily be cleaned if you dissemble a few parts. It didn't look promising. The seal ring broke into two pieces. But when I put it back together, it works. The leak is just a design fault, putting stress on the tube all the time. You can use tape to stop the leak if nothing else. The tube is for the hand tool, a mini steamer for the stairs, which is impossible for the full steamer to get on.
I'm not a fan of Hover but they do have supply of parts and repair if you need.
Saturday, July 14, 2012
Friday, June 29, 2012
Getting rid of spiders and their webs with soapy solution
I have an organic garden. That means a lot of weeds, bugs, and hence spiders. On a slope with irregular growing ivy and occasionally tall weeds, it's Halloween everyday. You can see spider webs covering the slope when the sun comes up, shining on the morning dew on the web.
Of course diluted dish washing liquid (for hand wash) is instant kill for spiders. I have yet to encounter bugs that cannot be killed by it.
I tried the soapy solution on the webs. Instantly the altered surface tension changed the entire structure of the web. It disappears because the fine fibres got bundled into larger strands. If you spray closer, you can dislodge the anchor points to totally destroy the web.
It's true there's easy ways to destroy the spider webs so my slope don't look like Halloween everyday. A pole or a rack will do nicely. But you may have delicate plants or surfaces that you don't want to disturb.
Once sprayed, the web will be useless and any spider in it killed. It will also kill other bugs, food for the web hunters. Hopefully they don't return. I'll let you know.
Of course diluted dish washing liquid (for hand wash) is instant kill for spiders. I have yet to encounter bugs that cannot be killed by it.
I tried the soapy solution on the webs. Instantly the altered surface tension changed the entire structure of the web. It disappears because the fine fibres got bundled into larger strands. If you spray closer, you can dislodge the anchor points to totally destroy the web.
It's true there's easy ways to destroy the spider webs so my slope don't look like Halloween everyday. A pole or a rack will do nicely. But you may have delicate plants or surfaces that you don't want to disturb.
Once sprayed, the web will be useless and any spider in it killed. It will also kill other bugs, food for the web hunters. Hopefully they don't return. I'll let you know.
Thursday, June 28, 2012
Homemade carpet cleaner so good that it remove stains
I have a so called carpet steam cleaner. It's too big too heavy and too troublesome to use. And it's not that good.
People put baking soda on their carpets to clean. People put vinegar solution on their carpets. Some people put both. The question is how good it is and how practical than carpet shampoo and steam cleaners.
After hand wash using microfiber cloth only, it's as good as oxiclean! And I tried at the heavy traffic area that looks almost black. Originally it's beige. We use to use oxiclean solution to remove stains. The problem is that it will create a light spot on the old carpet. After the baking soda and vinegar treatment, it's the same color as the oxiclean treated spot.
Now the practical process. Sprinkle baking soda all over the carpet. Work the power evenly with a brush, or use the electric brush of a steamer. Spray the carpet slightly wet with a solution of 1 part warm water and 1/4 part distilled vinegar. Then use a brush to clean like a shampoo, or use the electric brush. Work more on the stains. Wipe away wetness and lift the dirt with a microfiber cloth. I don't even have a brush so I did everything with a microfiber cloth. It doesn't look much when finished. But when it's completely dry after a while, it will look the same as treated by oxiclean.
I don't know what's the long term effect on the carpet. And you should try in a small area first. But our carpet is almost black and worn out at the high traffic area.
Baking soda is mildly alkaline and itself a good cleaner for grease and water stains on the bathroom. If you leave it on the carpet it will absorb odour. It is also an abrasive power but it's too fine and soluble to damage any surface.
Vinegar is mildly acidic, and a good cleaner to dissolve grease and water stain. You should dilute it because of the smell, and the cost if you buy it from the supermarket.
When they react, carbonic acid is first formed with heat giving out. I would think that provide extra cleaning effect. The carbonic acid should be stronger than vinegar and highly reactive. The carbonic acid will then disintegrate into water and carbon dioxide. What left is sodium acetate, a salt that is also used to replace salt and vinegar in fish and chips. A salt is like common salt, which is transparent but white when in power form. It will not turn into anything or change colour.
I use a microfiber cloth to lift the dirt because in repeated use, the microfiber cloth is less dirty than say cotton. If the cloth is not too dirty I rinse it once in water. Once a while I put it in the washing machine.
Update: It is always a mystery of using both baking soda and acid. Actually the reaction absorbs heat. When you combine both you neutralize each other. But many people swear they saw better results and so do I. Now my thinking is that the extra cleaning effect is not chemical, but physical. It's like you rub acid into hard to reach areas of the surface. And the fine baking soda powder do the rubbing.
People put baking soda on their carpets to clean. People put vinegar solution on their carpets. Some people put both. The question is how good it is and how practical than carpet shampoo and steam cleaners.
After hand wash using microfiber cloth only, it's as good as oxiclean! And I tried at the heavy traffic area that looks almost black. Originally it's beige. We use to use oxiclean solution to remove stains. The problem is that it will create a light spot on the old carpet. After the baking soda and vinegar treatment, it's the same color as the oxiclean treated spot.
Now the practical process. Sprinkle baking soda all over the carpet. Work the power evenly with a brush, or use the electric brush of a steamer. Spray the carpet slightly wet with a solution of 1 part warm water and 1/4 part distilled vinegar. Then use a brush to clean like a shampoo, or use the electric brush. Work more on the stains. Wipe away wetness and lift the dirt with a microfiber cloth. I don't even have a brush so I did everything with a microfiber cloth. It doesn't look much when finished. But when it's completely dry after a while, it will look the same as treated by oxiclean.
I don't know what's the long term effect on the carpet. And you should try in a small area first. But our carpet is almost black and worn out at the high traffic area.
Baking soda is mildly alkaline and itself a good cleaner for grease and water stains on the bathroom. If you leave it on the carpet it will absorb odour. It is also an abrasive power but it's too fine and soluble to damage any surface.
Vinegar is mildly acidic, and a good cleaner to dissolve grease and water stain. You should dilute it because of the smell, and the cost if you buy it from the supermarket.
When they react, carbonic acid is first formed with heat giving out. I would think that provide extra cleaning effect. The carbonic acid should be stronger than vinegar and highly reactive. The carbonic acid will then disintegrate into water and carbon dioxide. What left is sodium acetate, a salt that is also used to replace salt and vinegar in fish and chips. A salt is like common salt, which is transparent but white when in power form. It will not turn into anything or change colour.
I use a microfiber cloth to lift the dirt because in repeated use, the microfiber cloth is less dirty than say cotton. If the cloth is not too dirty I rinse it once in water. Once a while I put it in the washing machine.
Update: It is always a mystery of using both baking soda and acid. Actually the reaction absorbs heat. When you combine both you neutralize each other. But many people swear they saw better results and so do I. Now my thinking is that the extra cleaning effect is not chemical, but physical. It's like you rub acid into hard to reach areas of the surface. And the fine baking soda powder do the rubbing.
Tuesday, June 26, 2012
Super homemade glass cleaner
At last I found somebody have similar interest but with more time - Crunch Betty. This is the glass cleaner formula from her blog, well experimented in different ingredients.
1 cup hot water
1/8 cup vinegar
1/8 rubbing alcohol 70% isopropyl (first aid)
1/2 tbsp cornstarch
No matter how awesome baking soda is, it can't clean glass with streaking, and a lot of it.
This formula works without streaking. It's easy to make instantly. It cost very little. The result is perfect if your glass isn't too dirty, as in exterior windows.The vinegar smell goes away very soon, and smelling not as strong as my CLR biodegradable.
The best use of it is via a dry microfiber cloth. There is no lint. I wash them after use and they last a long time. But themselves aren't a green product.
For the outside window, you need some elbow grease if you clean them once a year. I don't know if other glass cleaners fairs better. But I can use baking soda first to rub out the stains, rinse the glass thoroughly, then the super glass cleaner.
Being professional, the problem is that her blog is full of other not so good stuff to make up the numbers. Do you want to make your own shampoo?
The reason I like this one is that I can safely use it around the kitchen windows without moving away the other things that may one day in touch with food or eating utensils.
A bad one for example, commonly found all over in other places, is use vinegar mixed with water for carpet cleaning. The mixture is half and half, making it quite expensive compared with carpet shampoo. One gal of carpet shampoo can be used many many times diluted. One gal of vinegar last a few times at most. And if you put that much vinegar on the carpet all over the place, the smell ...
1 cup hot water
1/8 cup vinegar
1/8 rubbing alcohol 70% isopropyl (first aid)
1/2 tbsp cornstarch
No matter how awesome baking soda is, it can't clean glass with streaking, and a lot of it.
This formula works without streaking. It's easy to make instantly. It cost very little. The result is perfect if your glass isn't too dirty, as in exterior windows.The vinegar smell goes away very soon, and smelling not as strong as my CLR biodegradable.
The best use of it is via a dry microfiber cloth. There is no lint. I wash them after use and they last a long time. But themselves aren't a green product.
For the outside window, you need some elbow grease if you clean them once a year. I don't know if other glass cleaners fairs better. But I can use baking soda first to rub out the stains, rinse the glass thoroughly, then the super glass cleaner.
Being professional, the problem is that her blog is full of other not so good stuff to make up the numbers. Do you want to make your own shampoo?
The reason I like this one is that I can safely use it around the kitchen windows without moving away the other things that may one day in touch with food or eating utensils.
A bad one for example, commonly found all over in other places, is use vinegar mixed with water for carpet cleaning. The mixture is half and half, making it quite expensive compared with carpet shampoo. One gal of carpet shampoo can be used many many times diluted. One gal of vinegar last a few times at most. And if you put that much vinegar on the carpet all over the place, the smell ...
Wednesday, June 20, 2012
Baking soda should have put many cleaners out of business
As an acid, it's just too weak. So the acid I prefer is the strongest one easily found in stores, and biodegradable too. It smells because it's an organic acid, masked a little by natural fragrant I guess. It works well - water stains, sink, toilet bowls, faucets.
Because baking soda, sodium bicarbonate, is a weak alkaline, I don't even tried it to clean anything.
I just replaced my microwave hood combo. The grease buildup is terrible, over a period of over 10 years. My wife clean it everyday with detergent. I tried everything from time to time, but can't deal with the grease using my favourite acid, hydrogen dioxide, and alcohol.
I can reduce the grease buildup, but I'm afraid to deal with it. I can remove a bit on the surface but the grease become gluey on the surface and it's terrible to clean the cloth and brush afterwards. The same thing goes for the grease filter. I never can clean the thing thoroughly with whatever not so toxic chemical or cleaner I can find.
Out of desperation I searched the web again. This time I found baking soda. It was amazing. I know caustic would work but it would burn your skin too. I was amazed how a mild alkaline would work so effective. Now my over 10 year old kitchen is shinning white, blinding my eyes.
The grease buildup on the stove and oven range simply gone by wiping with a damp cloth sprinkled with baking soda. The plastic surface becomes a mirror. All the finger marks are gone. On the coated metal surface, even long ago baked in food residue are removed by repeated wiping with a scrounging pad for non-stick surfaces. If you never damaged the surface with tough brushes, your range will look brand new again. Black hardened grease stains around the outside of the oven are now gone. I may clean the inside of the door too. See the reflections on the range and contrasts to the grep metal parts that I haven't cleaned seriously for 5 years.
It works on the grill and bake racks and pans too. They are not turning brand new, but the accumulated stains are getting out rather than getting worse.
My wash pad got contaminated with baking soda, and now my heavily stained mug are losing it's stains. I didn't even tried to remove the stains.
I think the chemistry is that sodium bicarbonate reacts with grease to form soap, which is a cleaner of course. Soap is soft so you can just wipe it away.
Baking soda would not work on some surfaces such as wood. The resultant soap (or something else) got into the wood grains and stain it.
For wood the only think sensible thing is rubbing alcohol, which simply dissolves grease. Alcohol will work well on grease, but not as dramatic or cheap as baking soda, and not much on hardened grease stains.
Baking soda is a pretty good cleaner for kitchen tiles, and works on the grout somewhat. But hydrogen peroxide is the better whitener for grout, and you can combine them.
But much more use is written on the Arms and Hammer box. It's a shame that they don't market it as a miracle cleaner and put some in the cleaner aisles. And the cardboard box is laughable. Seriously how can you clean carrying a paper box around without a cap?!
Sunday, December 25, 2011
Small pet house review
The rabbit house described here is now almost completely different. But actually the first design is almost very good, needing just some customization to be perfectly practical.
I couldn't do customization that at the time. Because I didn't know that sawing acrylic with metal blade is a piece of cake. It should be easy and economical to use thin glue to weld the acrylic together. Yes, do don't have perfect edge for that but you can reinforce any 90 deg joint with small triangular wedges touching the two surfaces.
Almost I will custom make using acrylic starting from the exterior, that is, everything. An unsuitable cage for a dog for travel in summer is totally unsuitable no matter how you custom it.
You hardly need and structural acrylic sheets. 1/4" will be tough enough to support anything, while still soft for jumping on and on impact. The other parts such as walls can be 1/8 to 1/16. There are cheap polycarbonate sheets that are thin but strong. You always need a saw, with metal blades. Cutter just don't work unless your sheet is very thin.
There should be proper doors and windows to make it easy to insulate in winter, and to open widely in summer.
The housing should be easy to add insulation material such as cheap foam sheets, or double walled as in double glazing windows. And in summer, shades. There should be confined cavities and ramps to simulate burrows, while they should be easy to remove and clean. Draft proof in winter and plenty of circulation in summer.
The housing should be modular with dry sleeping area, wet drinking area, food area and bathroom area. Though it looks like that they pee when they drink, and poo when they eat. So you have to combine the right areas.
The other sense of modular is that you can take parts out to clean individually. It's hard work if you need to take out everything to take the floor to wash clean.
The housing should be designed for accessibility. If you have one door for everything in a large cage, you can do anything at the back. I ended up taking off the top everyday to refill food, water and to clean.
An elevated platform for sleeping is a good idea. They will be dry even when there is a rain storm, even the roof is leaking from all sides. There are spaces for the dirt to go and you can scoop them up less frequently.
Wet cleaning is a bad idea. It takes a long time to dry. Unless you collect and flush everything into the toilet, the poops are very good food for many bugs.
Cleaning should be designed to be dry, especially if you intend to use the vacuum cleaner. I have a bagless so the suction isn't a problem for all the litter and poop. And you can empty the collection chamber easily. But mostly I use the scoop and spade. It's convenient and efficient. If it's an outdoor cage, it doesn't need to be squeaky clean, but should be in equilibrium without dirt accumulating.
For food I use a soda bottle with a hole near the bottom to allow the pellets to flow out onto an attached small plate. The bottle can be taken apart from the middle to refill.
The upside down bottle for water is a good idea. But if you can custom where the pet sucking bottles are hanged easily and refill easily, you may prefer that. Water in the bottle will never be contaminated. If you separate the drinking area, you have to build something to hold the bottle without toppling. Due to non custom plumbing parts, my upside down bottle ended up dripping slowing or the water level too low for the narrow opening. At the end I use a large juice bottle with a hole near the bottom. And then put the bottle on a shallow container. It's exactly the same as upside down bottle but stable. The drinking hole should be placed as high as possible to prevent dirt and poop from getting in and contaminate the whole bottle of water.
It's good to reuse clear plastic bottles because you can sanitize using the sun effectively.
The all important bathroom area. All you need is a 1x1' box, 2" deep. And they will toilet train themselves as long as there is litter. There's no use for a much larger box. The trick is to use layers of material. Absorbent layer at the bottom for odor control, and the pee have to go somewhere. Soft absorbent material for first defense. Some bulk filling material in the middle, such as cheap pine chippings. So the poop have somewhere to go instead of being stumbled on all the time. If you have an isolated layer, you can put in industrial absorbing materials that is not safe for pets to chew.
I gave up the heating as I have to run a wire to the cage, now far away from the house. Instead I just cover the whole cage with a nylon sheet, another layer of insulation and shelter. Recently I thought of filling a large milk bottle with hot tap water, and put it in the cage before I go to sleep. The warmth will last for hours.
I couldn't do customization that at the time. Because I didn't know that sawing acrylic with metal blade is a piece of cake. It should be easy and economical to use thin glue to weld the acrylic together. Yes, do don't have perfect edge for that but you can reinforce any 90 deg joint with small triangular wedges touching the two surfaces.
Almost I will custom make using acrylic starting from the exterior, that is, everything. An unsuitable cage for a dog for travel in summer is totally unsuitable no matter how you custom it.
You hardly need and structural acrylic sheets. 1/4" will be tough enough to support anything, while still soft for jumping on and on impact. The other parts such as walls can be 1/8 to 1/16. There are cheap polycarbonate sheets that are thin but strong. You always need a saw, with metal blades. Cutter just don't work unless your sheet is very thin.
There should be proper doors and windows to make it easy to insulate in winter, and to open widely in summer.
The housing should be easy to add insulation material such as cheap foam sheets, or double walled as in double glazing windows. And in summer, shades. There should be confined cavities and ramps to simulate burrows, while they should be easy to remove and clean. Draft proof in winter and plenty of circulation in summer.
The housing should be modular with dry sleeping area, wet drinking area, food area and bathroom area. Though it looks like that they pee when they drink, and poo when they eat. So you have to combine the right areas.
The other sense of modular is that you can take parts out to clean individually. It's hard work if you need to take out everything to take the floor to wash clean.
The housing should be designed for accessibility. If you have one door for everything in a large cage, you can do anything at the back. I ended up taking off the top everyday to refill food, water and to clean.
An elevated platform for sleeping is a good idea. They will be dry even when there is a rain storm, even the roof is leaking from all sides. There are spaces for the dirt to go and you can scoop them up less frequently.
Wet cleaning is a bad idea. It takes a long time to dry. Unless you collect and flush everything into the toilet, the poops are very good food for many bugs.
Cleaning should be designed to be dry, especially if you intend to use the vacuum cleaner. I have a bagless so the suction isn't a problem for all the litter and poop. And you can empty the collection chamber easily. But mostly I use the scoop and spade. It's convenient and efficient. If it's an outdoor cage, it doesn't need to be squeaky clean, but should be in equilibrium without dirt accumulating.
For food I use a soda bottle with a hole near the bottom to allow the pellets to flow out onto an attached small plate. The bottle can be taken apart from the middle to refill.
The upside down bottle for water is a good idea. But if you can custom where the pet sucking bottles are hanged easily and refill easily, you may prefer that. Water in the bottle will never be contaminated. If you separate the drinking area, you have to build something to hold the bottle without toppling. Due to non custom plumbing parts, my upside down bottle ended up dripping slowing or the water level too low for the narrow opening. At the end I use a large juice bottle with a hole near the bottom. And then put the bottle on a shallow container. It's exactly the same as upside down bottle but stable. The drinking hole should be placed as high as possible to prevent dirt and poop from getting in and contaminate the whole bottle of water.
It's good to reuse clear plastic bottles because you can sanitize using the sun effectively.
The all important bathroom area. All you need is a 1x1' box, 2" deep. And they will toilet train themselves as long as there is litter. There's no use for a much larger box. The trick is to use layers of material. Absorbent layer at the bottom for odor control, and the pee have to go somewhere. Soft absorbent material for first defense. Some bulk filling material in the middle, such as cheap pine chippings. So the poop have somewhere to go instead of being stumbled on all the time. If you have an isolated layer, you can put in industrial absorbing materials that is not safe for pets to chew.
I gave up the heating as I have to run a wire to the cage, now far away from the house. Instead I just cover the whole cage with a nylon sheet, another layer of insulation and shelter. Recently I thought of filling a large milk bottle with hot tap water, and put it in the cage before I go to sleep. The warmth will last for hours.
Wednesday, May 4, 2011
In praise of the top-freezer refridgerator
The top-freezer fridge is efficient and reliable, and had been the only design for ages. The electricity is cheap even if your fridge is inefficient. The cost of a luxury model is not much spread over some 10 years or more. But if you stick to the top-freezer design, you are green.
For decades, the fridge grows in size. People go to shop every week instead of every day. You want to put everything possible in the fridge in case you need it one day. But it cannot grow any deeper or you will have difficult getting things out. It cannot grow any wider or the door will be a danger to yourself, or just an obstacle in the house. It cannot grow any taller or it will be unstable. But if you put the big box at the corner, no one will be bothered.
Any larger fridge you need two doors. The side by side is a joke design. The whole fridge is bigger but both the freezer and the fridge is narrower. It's irritating when you have trouble putting a pizza into the freezer! Side by sides are also not as deep as a top-freezer fridge. You can't put two plates of anything on the same self.
That is not all. The whole design of SBS is to make the freezer narrow and to justify the total size of the freezer. Therefore the freezer is narrow, just enough for a pizza. A large portion of the freezer is a huge ice storage chamber, and a giant ice crusher. And a lot of space is used for ice and cold water delivery. The whole ice making and accessories is the most often failing parts. Though I never have problem with them.
The idea of a bottom freezer seemed very sensible. Because you use the fridge a lot more than the freezer, you should be facing the fridge and fetch things right in front of you. But actually it's another joke. Because you cannot have a little freezer door down at the floor, you need a freezer with a drawer. And how do you make ice when opening and closing the drawer all the time?
For decades, the fridge grows in size. People go to shop every week instead of every day. You want to put everything possible in the fridge in case you need it one day. But it cannot grow any deeper or you will have difficult getting things out. It cannot grow any wider or the door will be a danger to yourself, or just an obstacle in the house. It cannot grow any taller or it will be unstable. But if you put the big box at the corner, no one will be bothered.
Any larger fridge you need two doors. The side by side is a joke design. The whole fridge is bigger but both the freezer and the fridge is narrower. It's irritating when you have trouble putting a pizza into the freezer! Side by sides are also not as deep as a top-freezer fridge. You can't put two plates of anything on the same self.
That is not all. The whole design of SBS is to make the freezer narrow and to justify the total size of the freezer. Therefore the freezer is narrow, just enough for a pizza. A large portion of the freezer is a huge ice storage chamber, and a giant ice crusher. And a lot of space is used for ice and cold water delivery. The whole ice making and accessories is the most often failing parts. Though I never have problem with them.
The idea of a bottom freezer seemed very sensible. Because you use the fridge a lot more than the freezer, you should be facing the fridge and fetch things right in front of you. But actually it's another joke. Because you cannot have a little freezer door down at the floor, you need a freezer with a drawer. And how do you make ice when opening and closing the drawer all the time?
Subscribe to:
Posts (Atom)