The gasoline method works great. I would've done that to the ones in my front yard, but the hole was too near to a couple of pine trees, so I couldn't risk it.

Here's a method that a friend and I used back in the days when kids could still buy those little firecrackers called "cherry bombs". There was a hive of yellow jackets in an old groundhog hole, and one of them came out and stung me on the ear while we were playing some distance away. Well, me and my friend came back around midnight and tossed a couple of lit cherry bombs in that groundhog hole. Cherry bombs made a hell of a bang. The concussion killed 'em all stone dead. We checked the next day and there were no yellow jackets stirring in that hole any longer.

I think it's a damn shame that a bunch of pussyfooting lawyers and petty bureaucrats and misguided do-gooders have deprived the boys of Canada of their cherry bombs, that's what I think. And I notice that kids are shooting people with guns now, which I never heard of a kid doing back when I was a kid. Big lot of good it's done taking away their cherry bombs!