Having seen the occasional trashcan get infested with maggots, and seeing them survive several different household cleaners, I got to wondering. Is there a common/easy to get chemical or somesuch that will kill these things on contact or at least really fast?
Grandma used to dispatch them quite readily with boiling water. If these are a problem at your own home, consider a fine-mesh screen on top of the container, before you put the lid on. No entry=no eggs=no maggots. Alternatively, don’t put out anything attractive to flies, so they won’t come and lay eggs. Rinse out all cans, jars, bottles etc. before you dispose of them, it only takes a little food waste to sound the dinner bell. A garbage disposal is great for obviating this summertime nuisance.
Plain household ammonia. Dump a splash into the garbage can – it doesn’t take a gallon of the stuff either, just a 1/4 cup or so – and pop the lid on. The fumes will take out the maggots the ammonia doesn’t actually touch. Works great.