About every 4-6 weeks I refresh my airlocks with clean sanitizer solution. Interestingly this year was a bad year for fruit flies in my basement winery work area. Used a vinegar trap and caught a few, very few. So today it was Airlock-Refresh day. I found out where all those Fruit flies went to. Body counts ran from 2-3 to a dozen or more in some airlock. Weird thing is very few were visible until I emptied the airlocks in my sink. Good news is of course when you use StarSan in the airlocks, they can't swim through that for long. Sorry if you thought this was an idea for getting rid of Fruit Flies. My experience with the vinegar trap is meh, something you can do but... they seem to know Apple Cider vinegar from the real deal and they prefer the real deal. Maybe next time I'll dip out a couple of ounces for the must and put it in a trap.