Best Fruit Fly Trap The More Hassle, but Works Best Method (We're convinced this is the best home-made design out there!) Get yourself an empty 2-litre pop bottle. Take the cap off the bottle. This'll be difficult after the next steps, so do it now. Cut the top off the bottle, about an inch (2.5cm) below where the curvy part stops and the straight side of the bottle starts. (Cut the straight part, not an inch above on the curved part.) Put an inch or so of one (or more) of the following into the base of the bottle: Vinegar, Apple Cider, Wine, Orange Juice. (Leave it standing for this, obviously.) Turn the other piece, the top piece, of the bottle