Two step bug killing using organic ingredients

I had great success using soapy solutions to kill ants and a lot of other bugs.  But I noticed that flies return to life after they are dried.  And that big spiders are very much disturbed but not dying.

Someone suggested to add vinegar to the soapy solution to kill flies.  It worked.  But unfortunately I used to aim at flies like AAA.  So the whole area smell of vinegar after the battle.

It dawned on me that I can use two steps to get the best of both worlds.  The bugs aren't going away after the first.

The first step is to immobilize the bugs using soapy solution.  I use Dr Bronner's organic liquid soap.  1 tsp to 1 cup of water.  I just have it and it should be safer than dish washing liquid.  You can use a more concentrated solution for big spiders, and less concentrated for ants.

The ants still dies.  Flies will be grounded and struggling.

For step two, you can put a few drops of anything strong to kill the bugs.  A few drops of 70% rubbing alcohol will kill flies in seconds.  Alcohol are safe on most surfaces and skin.  You can also use vinegar, hydrogen hydroxide, or citric acid.