Effective home remedies for eliminating gnats are apple vinegar, sprinkling sand on damp soil in potted plants and making gnat traps using petroleum jelly. Gnats prefer to lay eggs in damp soil or rotten fruit, so throw away such items before attempting home remedies.
Avoid overwatering indoor potted plants when dealing with a gnat infestation; gnat larvae thrive in damp soil. Let the damp soil dry out for a few days to kill any larvae. A small layer of sand can be sprinkled over the top of the soil to trick adult gnats into thinking the soil is dry.
A home gnat trap can be created using apple vinegar and a paper cone. Poor a small portion of apple vinegar into the bottom of a jar or glass. Take a sheet of paper, roll it into a cone and place it in the glass, so the tip of the cone is suspended in the middle of the glass. Place the trap in an open space where gnats were observed.
Another home remedy can be made using a piece of yellow plastic and petroleum jelly. Smear petroleum jelly on the piece of yellow plastic and hang it in an open space where gnats are visible. Gnats are attracted to the color yellow. The petroleum jelly traps the gnats when they land. To reuse the trap, simply wash the plastic off and reapply petroleum jelly.