Perfect carpet cleaning with perfectly safe ingredients

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.