I recently was at my friend’s house and we were eating outside under her umbrella-ed table. I looked up and there were a few zip lock baggies half full of water with 5 or 6 pennies in each pinned to the umbrella so they were hanging down. I thought they were there to weigh down the umbrella or as part of some crazy decorating scheme but in fact they were there to keep the flies away.
My friend read somewhere that flies are intimidated by the pennies’ brightness or shiny quality when they are in the water. They are either blinded or threatened - and they stay away. She swears by it although I am skeptical. I have more of a problem with bees, but if I had flies, it would be worth a shot. If you have tried this, did it work? Let us know!