[blincoln]

I've used a shop vac as a first step, but if it's the only step, won't the queen survive and make more wasps? Unless you left it running for so long the queen starved to death, I mean.

My current approach is to wait until after dark, then fill up the nest entrance with spray foam (while wearing a beekeeper suit, just to be safe). I don't think that would work for walls, though - they'd probably find another way out.

[bigstrat2003]

In fact, that approach is explicitly warned against for walls. When they can't get out their former entrance, they will start to chew through the wall to make a new one - and there's no guarantee that new entrance will lead to the outside, rather than your living room.

[foobarian]

My problem was the nest was hard to reach, and I was afraid that even if spraying did manage to kill the wasps, I would be left with a gross wet decomposing mass in the wall causing rot and water damage. I still need to figure out how to remove the existing nest but I'll wait until it's vacant :-)

[tmerc]

My first time having yellow jackets in my wall, I sprayed poison in the entrance. They found a new way to leave the nest that was into my kitchen. That's when I stopped using poison.

[samcheng]

I've needed two passes in the past, a few days apart. One to catch all of the adults, and another to catch any new wasps that emerged immediately after the first pass.