Wasps can be killed using a commercial fumigator or by spraying a mixture of soap and water on the wasps' nest. One can also drown wasps, place the nest in a plastic bag or remove the nest to encourage wasps to move elsewhere, according to Horizon Services.
Horizon Services recommends killing wasps at night or in early spring when the wasps are least active. At night, wasps can be killed by placing the nest inside a plastic bag and allowing the bag to sit for several days. If the nest is in the ground, place a garden hose in the opening where the nest is located and turn the water on until the nest is immersed.
To use a commercial fumigator, follow the instructions on the packaging. Most fumigators are placed near the nest and triggered. Some fumigators require covering the nest to concentrate the pesticide. Wasp nests that are located outdoors can be removed in early spring by removing and disposing of the nest.
For a nontoxic solution to kill wasps, the University of Nebraska recommends a mixing a solution of 5 percent dishwashing liquid in water. Make the mixture in a garden sprayer and use it to kill wasps as they leave the nest. Inside the home, Horizon Services recommends pouring orange juice into a lidded jar until the jar is about 1/2 full, then punching a hole in the lid of the jar to allow wasps to enter. Spread a small amount of jam on the bottom of the lid and place it on the jar to attract and trap wasps.