I’ve killed many a musca domestica, aka house fly, in my day.
As a child visiting Wisconsin, one of my favorite barn chores was poisoning the little buggers. Grandma had an old-fashioned pump sprayer, which she filled, I’m guessing, with a capful of dichlorodiphenyltrichloroethane, aka DDT, and water. This was long before we knew that the substance was a scourge to birds, especially ones high on the food chain like hawks and eagles. So spray I did, pumping clouds of toxic vapor in the air.