I tend to use a shop vacuum to get rid of undesirable wasp nests. Fill the tank with a few litres of water so the victims have something to drown in, point the tube at the nest entry or whatever entry the wasps use and switch it on for an hour or so. As soon as there is some disturbance most of the resident wasps will exit the nest to defend it so you'll get the resident population in only a few minutes. Keep the vacuum in place for a while to catch those which were out and about. Once you've got (most of) the workers the nest will die out if left alone. If you can reach it you can knock it down and drown or burn it, if it is in a wall somewhere that is not an option.

Don't forget to put water in the tank or you'll be met by a cloud of angry wasps when you open it.