While serving in the US Army
my wife and I lived in a cockroach
infested trailer in southern Georgia
-- near Savannah. Every time we'd turn the kitchen lights on there would be a mad scrabble across the kitchen linoleum
as a half-dozen roaches scurried for the exits. Now, insects don't bother me that much, but my wife really is disgusted by them, so I'd have to make an attempt to kill them.
I would dutifully open the cupboard under the sink and grab the nearest aerosol can, then I'd start spraying the little bastards. My range of choices usually amounted to various aerosol furniture polishers, disinfectants, and the usual under-the-kitchen-sink products. None of them did a particularly effective job. Sometimes the roaches would appear dead. I'd scoop them into the garbage -- only to see them crawling back out a few minutes later.
But one night I went through this routine and saw the roaches suddenly start running fast in tight little circles -- then stop. Dead as a doornail. I didn't even read the can, just made note of its size and color. When it worked on repeated applications I finally decided to check and see what wonder product I was using --- clear acrylic lacquer. I was painting them to death.
Apparently they breathe through their bodies and I was coating them sufficiently to suffocate them. I'm just glad it was clear lacquer -- the little "highly waxed" spots on the linoleum tile weren't very noticeable. But the landlord probably wouldn't have been very happy if we'd left a polka-dotted floor behind.