Does Hanging Pennies in a Bag of Water Really Keep Flies Away?

Updated: Jan. 11, 2022

Not a fan of loose change? In the South, some people swear by using change in a bag of water to keep bugs at bay!

During the height of the summer months, pesky flies can ruin an afternoon on the porch with a glass of iced tea. The bacteria-carrying pests are persistent, even with an artillery of insect traps, repellents and other devices. Because we’re collecting every trick in the book to keep flies at bay, we’re sharing one unusual idea: pennies in a bag of water.

Learning how to keep bugs out of your kitchen is one thing, but keeping them away from the porch proves to be more challenging!

Why Do People Hang Pennies in a Bag of Water?

According to Wide Open Country, zip-top bags filled with water and a few pennies adorn many restaurants, porches and doorways in the South to keep flies away.

Supporters of this DIY fly repellent claim success based off a couple of theories, but the most popular has to do with the mechanics of a fly’s sight. The eyes on a fly are more complicated than human eyes; for flies, Orkin says their eyes are compound, or made up of thousands of individual lenses that are very perceptive to changes in light.

So, when light hits the bag of water filled with shiny pennies (or even pieces of aluminum foil, in some cases), the thought is that it refracts and confuses the insects. Overwhelmed, they fly away and hang around somewhere else.

Does It Work?

This is up for debate all over the internet. Some people swear by it, sharing success stories on blogs and Facebook, while Snopes says that scientific experiments show it may not make a difference.

I can’t say for sure, since I haven’t tried it myself. It’s currently winter where I’m writing from—with snow on the ground and a -25°F windchill—so not many flies are buzzing around. In summer, though, this is a trick that I’ll have to put to the test.

You may also want to try hanging Irish Spring soap to keep flies away!