neurotoxins do breakdown with time, but the sicko bast-rd in me loves to watch the black widows, wasps, and cockroaches go through the muscle spasms before they stop moving from death. I haven't seen any cockroaches to kill since leaving the air force, but every year, I get to kill a few wasps and black widows with my preferred Nerve Agent.
For other spiders, i also like the Lysol flame thrower method, but for legal reasons, as they say on mythbusters, don't ever try this at home, ever!!!.
Our household is the same we like to watch the Black Wida's curl, jump, almost could hear her scream then die. Lysol flame thrower is another fun activity when killing bugs.
So talking about cockroaches two months ago I had some in my house completely freaked me out - when I think of roaches I think of dirt and filth but I am a good housecleaner. Long story short I wasn't going to fool around with exterminating myself (as they only can be seen when i turn on a light then they disappeared) so I hired an exterminator for them and he took care of my ant problem too... Ends up he thinks I got them from Costco in a box, he said he had quite a few people in Folsom that week complain and we had all been costco shoppers... So beware when bringing home Costco boxes take a look before you bring it in the house.