Reusing coffee grounds offers benefits from fertilizing plants to repelling mosquitoes. Coffee grounds have a smoldering effect after you light them that keeps insects at bay. Also, reusing coffee grounds saves money. Some people use coffee grounds in a compost pile to feed worms and keep other insects away, according to the U.S. Environmental Protection Agency (EPA). Mosquitoes, like other insects, are repelled by the odor created from the coffee grounds burning.
Remove the coffee grounds from your coffeemaker and put them in an aluminum foil pie plate. Place them in a cool, dry area until they are completely dry.
Place the foil plate with the coffee grounds on a level surface, such as a table, outdoors. Make sure no animals or children have access to the area.
Add a few drops of barbecue lighter fluid to the coffee grounds. Do not saturate the grounds--this makes them burn too quickly.
Light the fluid with a long match to avoid getting burned. Then, allow the lighter fluid to burn off until the coffee grounds start burning and smoking.
Smother the fire with a large, damp towel or cloth by placing it over the top of the plate. The coffee grounds should continue to smoke and smolder. The smoke from the coffee grounds repels the mosquitoes.