Wasps in the attic can pose a serious safety risk. Wasp stings hurt most people and some people are allergic to the stings. Wasps nests are even more serious. A swarm of wasps can cause serious harm to adults and children. Killing wasps in the attic means getting rid of the nest and killing as many of the bugs as possible with insecticide. Because wasps are dangerous, use extreme caution when approaching them.
Put on several layers of clothing that cover every part of your body. Make sure to wear gloves to cover your hands. This creates a protective layer in case you are stung by a wasp.
Go up to the attic near sundown. You should not attempt to kill the wasps during the day because wasps are more active during the day and sleep at night. Go near sundown when enough light still comes in the attic to see the wasps and to walk safely around the attic.
Spray the nest with insecticide until it's completely covered and walk away.
Watch the nest from a distance of at least a few feet to see if any wasps move. If wasps don't fly out of the nest or crawl around after a few minutes, the insecticide worked. If wasps are still alive, spray more insecticide.
Come back to the nest after a few days to watch for live wasps. Once you're sure the wasps are all dead, pick up the nest and place it in a trash bag and remove.