Something funny I used on wasps a long time ago: Wet-Vac with the smaller bore hose (longer the better). Seems the tumbling in the ribs of the hose does them in. Did this to rescue the tractor one time.
Tried to kill all the critters in a nest the size of a small melon one time. Dead of winter out at the farm. thing was up in a tree. We figured with cold weather they would not fly. Knocked it on the ground, no problem. Drench it with gasoline, no problem(not enough gas it would seem). Light the darn thing-problem. Warmed air around hive let them fly. They all died eventually, but it did get a bit exciting.
I like to use the cheap yellow can of brake cleaner that AutoZoo sells for killing the little stingers. I'm somewhat alergic (not as bad as JRB-that's no fun, mate), so I take a pretty agressive stance against them. Killing one early in season is same aas killing ten later on in hte year.