A while back I was complaining about the smell of insecticide in my hangar coming from the tee hangar next door. It originally had a stifling smell of curdled milk. I finally had a chance to speak with the next-door occupant and asked him about it. He said it was malathion, and he used to to keep mud daubers out. I'm somewhat familiar with malathion since the county used to spray it for mosquitoes where I used to live, but this was a much stronger odor. Perhaps being confined within the tin box of a tee hangar intensifies it. Anyway I haven't seen any mud daubers lately...actually not any other bugs either, so it seems to be working.