Craig Lints sent me this method. It works! I too have killed thousands using his technique.
Heard you were having problems with yellowjackets. I have lost two hives so far. Once,they discover a weakness, they are like a shark feeding frenzy.
In the last couple days I have worked out something that seems to help.
What I've found is that removing the dead hive doesn't help. They just move down the line and start on the next hive. They have a homing instinct to the food source and even when it is removed they keep searching for a weakness in an adjacent hive.
So I got the idea of leaving the dead hive as a bait hive.
What I do is take an empty super and staple screen over the top. Then remove the lid on the bait hive and put a pan of soapy water on top of the frames. Cover this with the screened super. Wasps come in the bottom entrance and feed. When they leave, they sense the light above and try to leave via the top. They mob the screen trying to get out. Bouncing around in the top box, they eventually splash into the soapy water and die.
Two things are important. First not any way out of the top box. I tape it to the box below. And be sure the screen is very tight. The smallest gap and they will find it. Second, put blocks under the tray of soapy water so it is close to the screen, maybe an inch or so.
So far I have killed thousands.