The gasoline method sounds good, is fun, but doesn't get the results of eliminating the wasps from an underground nest. It'll kill some wasps, it's better at killing your lawn. Been there, done that.

Mostly they stay away and wait till the fire goes out, then resume normal activity.

Shopvac method is a one way ticket that will leave a blanket of dead wasps covering the bottom of the vac, and most importantly, no more wasps.