Where is the nest? In the ground? In a pile of rocks? I get wasp nests every year in a rock wall. I know when they've returned since they always get ticked off when I mow around the wall. I can see then coming and going in between the rocks. Since I know where they are I just use a can of any brand of wasp/hornet spray. The kind that can shoot 20 feet. I empty about 1/3 of a can each time they build a nest. The chemical acts quick and they usually drop within 1 second of the spray hitting them. I don't even wait for evening. If you know where the yellow jacket's nest is I would just unload a can of the spray on them.
