They can be dispatched at night with a bottle of creosote

My dad, who I hadn't hitherto thought of as a pyromaniac, once dispatched a wasps' nest in our garden wall with extreme prejudice -- using petrol. He poured it in through the topmost wasp-hole he could, stood well back, and threw a match at it. How he managed not to blow the wall to pieces I don't know, but the result was flames licking from every wasphole -- flames which convective draught through the nest turned into Bunsen intensity, in a sort of Cryptonomicon sort of a way. You could almost see the looks of surprise on the wasps' faces as their attack flights from the nest turned into neatly ballistic parabolas as their wings burned off.

Peter