Wait until evening when the wasps are home, and suit up for battle with loose clothing, gloves, eye protection and a hat. Spray the nest entrance with wasp and hornet spray. Monitor activity for two days and respray if needed. To deal with yellow jackets , follow the same procedure for wasps. But this time, plug the nest hole by packing it tightly with moist dirt.
Hornets are harmless unless disturbed.
If they are a nuisance, spray the nest with wasp and hornet spray. If they nest inside your home, wait until the first freeze and seal the nest entrance with silicone caulk.