Use a soap and water mixture.
If you’re against buying insecticides, you can simply use soap and water to get rid of small wasp nests. Just spray the nests with a solution made from two tablespoons of dish soap and mix it with some water in a spray bottle. The wasps will immediately die, as the mixture will block their breathing pores.
Use homemade DIY traps.
Wasp traps can be easily built at home if you simply remove the top from a large soda bottle and fill the bottom with a mixture of soda and fruit juice, mixed with some liquid soap. Then, turn the trap upside down, put the top back on, and hang it in your yard.
Kill individual emerging wasps.
Individual wasps can be easily eliminated with store-bought wasp killer sprays. Just follow the instructions on the label of the insecticide you buy, and spray the wasps as you spot them.