Hornets--one of the most aggressive types of wasps--pose a potential risk if they make a nest near a home, especially for people allergic to stings. In most cases, hornets make nests in trees or other tall structures, although it's not unheard of to find a hornets nest in the side of a home or in the ground. Due to their aggressive nature, always take proper precautions when it comes to hornet nest extermination.
Locate the hornet nest. A direct attack to the nest is perhaps the most efficient way to kill them. Stand outside and track their flying paths as this will likely lead you directly to the nest. Be cautious when you walk around to avoid an accidental step on the nest.
Mix a solution of 1 gallon hot water and just enough liquid dish soap to make it sudsy, usually three to four drops. Agitate the water until suds form. It's best to do this after the sunset when the hornets are less active.
Pour the solution directly in the nest and return to the house immediately to avoid potential stings.
Watch for hornets the following two or three days to see if they stick around. If the soapy water doesn't do the trick, pesticides may be necessary.
Apply a dust form of carbaryl or chlorpyrifos pesticide to the nest. According to the University of Minnesota Extension, dust pesticides tend to be more effective than liquid forms as they do a better job of reaching the entire nest. Follow the application directions on the product label to ensure the best results.
Fill in the nest area with new soil after the hornets either die off or move somewhere else.