I've used a neat trick with yellow jackets. Perhaps you can adapt it to your situation, though it would likely be difficult.
Yellow Jackets make nests in the ground, sometimes with multiple entrances.
The trick is this: if you block their exit in the normal way, they will just tunnel around the blockage, so you can't usually trap them to die, UNLESS you use an inverted clear glass bowl, over the exit/entrance. When blocked in this manner, their instinct to dig around the blockage never activates, because they sense that they are past the exit to the tunnel, as they buzz around in the bowl at the exit. They just die of starvation and thirst.
You locate the entrance during the day, and invert the bowl over it at night, when they are not as active. On an exit on a vertical wall, I would suspect duct tape would be useful to hold the bowl in place, and seal the exit.
a flat glass or plexiglass pane might work better for some locations, since it can be sawed to whatever shape an unusual opening may require.
Best of all, no expensive toxic chemicals.
Be careful, most wasps are most irritable at this time of year. Maybe they are angry that most of them must die soon.
