Looking at the posts on smoke, has any one tried using propane-powered foggers?
I was on a beekeepers course recently where an experienced beekeeper used an insect fogger with parrafin oil (instead of insecticide). Not only did it replace the smoke with a nice-smelling fog, but he claimed it also helped kill varroa. The droplets are small enough to suffocate the mites,but not the bees. It seemed extreme, but boy it worked a real treat.... except he has to call the local fire brigade first because the clouds of plume get people dialling 911 :D