Mix the dish soap with water so it because soapy. Mix one part of the soapy water with vinegar in a bowl, about 10 to 12 oz. of each.
Pour the mixture in three or four small plastic water or soda bottles. Put the lid on the water or soda bottles and close tightly. If you do not have the lid, put a piece of plastic wrap over the top and fasten it to the bottle with a rubber band or tape.
Shake the bottles so the inside of the bottles are wet with the mixture.
Poke tiny holes in the bottle with a knife. The holes should be just big enough for the gnats to fly through.
Place the bottles around your yard or inside your house.