For anyone that’s ever had their homes invaded by flies will know getting rid of them is easier said than done. Swatting or zapping the pesky insect isn’t as easy as it seems, while the sticky traps that usually hang from the ceilings of homes aren’t to everyone’s tastes.

However, there is one method which while it may seem peculiar at first glance, is said to be a very effective method from deterring flies and other flying insects. The technique doesn’t involve the flies getting hurt and even better, it only requires three easy-to-get things: plastic bag, water and… pennies. The deterrent is said to be popular in both the southern states of the US and also South America.

People hang the DIY anti-fly objects near windows, doors or seating areas to keep the flies away.

One person said her stepmother placed them in a goat barn and noticed “immediate results”.

“She put a half dozen pennies in the bag – she said she did make sure they were shiny pennies – and suspended it with bailing twine,” Amy Grisak wrote on plantersplace.com.

“She said there are a couple of flies, but nothing like the numbers she had prior to hanging the baggies.”

She added: “At least the baggies are a way to keep the flies away without chemicals or even purchased traps.

“This might seem like a whacky way to keep flies away, but if it works during the worst part of the fly season, it’ll be well worth having a few odd decorating accessories hanging on the walls!”

People have speculated that light refraction through the bag of water impacts the fly’s visions and confuses it. 

The Tennessee Farm Bureau, a non-governmental non-profit organisation, wrote: “A housefly has large complex eyes made up of thousands of simple eyes that don’t move or focus. 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."

It added some have claimed the flies are scared off as the pennies are magnified resembling the eyes of another insect or that they identify it as water which they don’t want to land on.

However, an expert from a pest control company in Georgia, US, told Fox News Digital in 2023 that there is “no credible scientific evidence” to suggest the method works.

Scot Hodges said: "I have visited properties that have had the penny-filled bags and flies, so my observation is that this is not something that can be relied on.”