An effective way to trap indoor gnats.

You can trap gnats using an easily made home trap.  Gnats and fruit flies are attracted to the smell of vinegar and sweetness, so ingredients are key.

Place some vinegar and and either dish washing detergent in a jar with a screw-on cap.  Sugar and bananas will also work when combined with vinegar.

Punch holes in the cap like you would with a childhood firefly jar.  Most gnats will not be able to get out and will drown in the vinegar.

Several traps will work better than one.  It’s not the best smelling solution, but it is effective.