The lakeside cottage I live in, while not technically drafty, is far from bug-tight. This means that once in a great while I will be sitting here at the keyboard of VFTP Command Central, only to have a droning buzz announce that a wasp is circling under the light fixture in the middle of the room. I'll grab the can I keep close to hand and wait for him to light on the dangling pull cord under the fixture. They always do. Then I give them just a little squirt. Just a dribble, really.
Of Gun Scrubber.
Unlike Wasp & Hornet sprays, which are pressurized to a brazillion PSI to spray nests under a house's eaves, you can make just a trickle come out the straw nozzle of a Gun Scrubber can, to drip down on the carefully-placed newspaper below. Along with the dead wasp. Because believe you me, it kills them Dead Right There. No flying around in their death throes, the way they do when nerve-gassed by more conventional anti-wasp ordnance.
Ah, Gun Scrubber. Cleans guns, kills wasps... is there nothing it can't do?