Frugal war on gnats!

I've waged a war on gnats in my kitchen. So far I've killed about 7 using this method...take a small bowl or measuring cup, and put some dishsoap in it. Then put a fair amount of vinegar in it. I use just plain vinegar, but I've heard some had to use apple vinegar. Let this sit on your kitchen counter for awhile (all day or night even) and then pour out. All the gnats sink down to the bottom of the bowl.