How about a fire hose? The water won't kill them, but will knock them to the ground so they can't swarm while you do whatever you decide the next step is (kerosene poured on the hive followed quickly by a match is a good start, if you can locate the hive.
Thankfully, the wasps around here are pretty tame. Every year, it seems they try to build a small nest in the patio umbrella, but never get more than about 6 combs built into it (usually just one or two solitary wasps). Once I knock the nest down for the year, they don't rebuild until the next year. Of course, that could also be because I spray the umbrella with insecticide in the summer...helps keep away the mosquitoes too, and better than spraying myself or the ground. Nothing helps keep away bumbling beetles under the porch light at night, or clumsy grasshoppers trying to fly around (or something very much like a grasshopper that takes wing...Ember likes chasing them when she gets outdoor privileges...she's just like a dog now, getting all excited to have her harness put on so she can go for a walk on the deck and lawn...she still gets scared the moment another person is outside though, but is getting better about it).
