This won't be pretty, but the fly trap works well!
You need a clean, one-gallon milk container with its cap. Cut four or five small holes all around the jug, about two inches below the slope toward the cap (near the level of the center of the handle). Mix 1/4 cup syrup and 1/4 cup apple cider vinegar and pour into the container. Fill to halfway with water and close cap.
Place these flytraps where the flies are thick. You will probably have to empty them every other day (I prefer making new ones because emptying old ones is pretty gross).
Jennifer www.stretcher.com/stories/02/02oct14b.cfm