What we used when I was younger and dumber was PGA, Pure Grain Alcohol. It will drop them dead in the nest or mid flight and any that manage to fly away will have one hell of a hangover.

Seriously, PGA, Gasoline, Diesel Fuel, Kerosene, Non-Chloronated Brake Cleaner, Soapy Water... They will all kill the pesky little ********. Some of these work faster than others.

My personal favorite was one I saw on the Discovery Channel (I think that's where I saw it anyway). Researcher and his assistant found an active ground nest. They fired up the melting pot directly over the hole in the ground and poured about ten gallons of molten zink down the hole. They then dug out the zink casting to see how far down and how many chambers the nest had. It was quit impressive how big and how deep some of those nest were.

Class III