The Tip Board
You need to be careful on this one. If you have a hornet's nest where you can get to it wait until the nest is calm (most likely at night) and use a cool whip dish or a large ice cream bucket with a small hole cut in the bottom. Carefully approach the nest and hold the bucket over the nest. Then spray your insecticide through the hole in the bottom. You will get 100% kill instead of missing a few by spraying from a long distance. When the hornets stop dropping into the bottom of the bucket, just slide the container down along the surface and scrape the nest off. You can then dispose of the dead bugs and the nest.