Do Pennies Keep Flies Away?

To make your own fly repellent, simply get a gallon-sized zip-loc bag, fill it half to 3/4 with clean water, and drop 3 or 4 pennies in the bottom of the bag. Once the bag is firmly sealed, it can be hung from or nailed to an eave near a doorway to keep the nasty critters from entering your home.

Do pennies repel flies?

Flies don't like water, and they don't like the colors given off from the pennies. Flies have compound eyes so the bags look like a giant body of water to them, therefore they leave.

Why does a bag of water with pennies keep flies away?

The best explanation is simple light refraction going through the bag of water that confuses the housefly. ... The fly bases his movement by light and the refracted light coming through the water in the plastic bag confuses the fly causing him to move on to a place that is easier on the eyes.