I had that problem a few weeks back. I took a small bowl and put half o.j. and half rum in it. Cover with plastic wrap and make sure it's snug. Poke tiny holes in the plastic wrap, not too big or they will fly back out. The longer it sits the more flies you will catch. Make sure you keep everything really clean, bleach and boiling water down your drains, trash covered and search for any rotting fruit or drinks around the house. Worked like a charm!