Fact or fiction?
We've tried this, and the results are mixed, but it sounds plausible.
If you put a penny in a baggie of water and hang it in a prime location, it will deter flies. Flies have many facets in their eyes. The way the sun reflects through the baggie and water has a prismatic effect on the fly, confusing it. One explanation says their GPS works on the directionality of the sun, and this throws it off. Another says, that the bag looks like a bee hive, and since they are afraid of bees, they stay away. Either way, it's worth a try next time you're having a BBQ outside. It's better than bug spray any day.
I hope you sleep better now that you know the answer.
