Does hanging pennies in a bag of water keep flies and pests away? Our entomologists say no, and suggest 3 methods that really do work

Exterior shot of large American home with large tidy lawn and small flowers and shrubs in foreground.

If you have ever been down to the southern states of America, you may have noticed hanging bags full of water and shiny pennies, and almost definitely wondered why?

As it turns out, this trick is supposedly a strange solution to keeping pests away from porches and yards, by reflecting sunlight, dazing and deterring bugs and keeping flies away outside.