Killing indoor gnats and fruit-flies/ worked for me!

Killing gnats and fruit flies--it works!!

 

This really works for me---I just placed it in a bowl. They went in and sunk!  The link where I found it is at the bottom.

A half cup of warm water plus two tablespoons of apple cider vinegar, a tablespoon of sugar, and about six drops of liquid dish soap just might be able to cure your gnat woes. They'll be lured in by the sugary mixture, but once they dip in for a drink, the sticky dish soap will trap them. Simply mix the solution together in a small bowl, place it in the areas where you've noticed the most gnats, and wait for results.

https://www.countryliving.com/home-maintenance/g27683756/how-to-get-rid-of-gnats/#:~:text=A%20half%20cup%20of%20warm,dish%20soap%20will%20trap%20them.