I have hornets or yellow jackets in my attic. Last year I tried to rid them with no avail. They were underneath the insulation with their nests on the drywall of the ceiling. I could hear their buzzing activity as I tried to sleep. I sprayed underneath the insulation and saw their nests on top of the ceiling drywall. This year they are back in two places. I see them going through the vents quite often. What's the best way to rid them?