Fly repellent - pinner said "I had to repin this again for you to see. YES IT WORKS! Oh my, it looks hokie but our temps have been upper 90's and no flies in my back yard have been spotted. I spoke with a women who grew up on a dairy farm and she swears by it. She said they used 5 pennies. Go figure."
Also on these boards
from Common Sense Homesteading
Non-toxic Home Pest Control – Avoid the Risks of Neurotoxic Pesticides
natural fly repellant @ Common Sense Homesteading water, penny set in the sun or hang in the sun wher you don't want flys. Trying this by our kitchen door this year