Classic Hacks: Repel Flies With A Plastic Bag

You may be planning a barbecue or two this summer — but how do you deal with all the flies? Do you use a spray, or do you just rely on the good old Aussie salute? As it turns out, the solution may be as simple as a plastic bag full of water.

Fly image via Shutterstock.com

We reported on this hack back in 2009, with many of our commenters agreeing that it did indeed keep the flies away (although some were less convinced). The idea is that you hang a plastic bag full of water at strategic places near your door or verandah, and the simulated movement will keep flies from settling. This explanation is from The Straight Dope:

Evidently, houseflies, being highly edible and defenseless, are nervous types, and don’t like to sit still when they see something moving nearby, because it could be a predator. The water bag acts a bit like a lens—try it some time—in which the movements of people in the area are reflected. Even if the fly is too far from the action to see it directly, it can see a shifting of light and dark in the water bag, which it interprets as nearby movement, and it will fly away from the bag.

The quote specifically mentions houseflies, however, and it’s unclear whether the technique also works on the more irksome Aussie bush fly — the kind that is attracted to humans and their bodily fluids. If your plastic bags are failing to keep the flies away, you could also build a DIY fly trap from simple parts most people have lying around the house:

Basically, cut an empty water bottle in half, turn the nozzle part upside down and insert it into the bottom half. Throw in some yummy goodies like old moldy beef and let the fun begin! Flies check in, but they don’t check out.

Lifehacker’s Classic Hacks is a regular segment where we dig up the most popular, useful and offbeat advice from our archives and update it for your modern lifestyle.