Wasp nest in wall, specialist comes out, sucks them all out, sprays commercial insecticide into wall cavity. Wasps that were out of nest at the time come back and get confused and piss off, couple days later they’re back and have found new unbefore seen holes to fly into, specialist tells me to buy trap and fill with meat. Buy canned ham and dump in trap. All wasps that came back are now in trap. Thanks Ham.