We had a batch of fruit flies this past year that didn't like cider vinegar, but loved soy sauce. Go figure. LOL We put a glass with a couple of inches of soy sauce in it on the counter, put plastic wrap over the top of the glass, and poked a couple of holes in the plastic with a fork. The fruit flies climbed in, but couldn't get out. We emptied the glass outside every few days, and then set it up again.
