Go out at night and run 1/2 pt. of petrol down their hole, then block it up with something if you can, probably won't be necessary, though. Alternatively, play the flame of a blowlamp on the hole entrance, they won't be able fly at you without wings.
Use spray-on wasp killer if they're in a hole in your house.
DIY a beekeepers veil with net curtain & some wire. Dress up, no skin exposed, and they can't get you. If the nest is in a bush, dress up like that, go out at night, slide a carrier bag around the nest, close the top, slide off the twig, run some petrol into the bag, it'll kill them fast.