How to drive away houseflies

Have you ever tried to wave off the flies that come near your food when you eat out especially at a not so clean eatery? In some food stalls, you will find that there are no flies around the food. Observe carefully, and you will find transparent plastic bags with water in them hanging around the stall.

Actually, these water-filled plastic bags serve a very good purpose - keeping the housflies at bay.
According to research, the water in the plastic bags act as a prism relecting light in all directions. The houseflies, upon seeing them, think that their predators are around and leave quickly.

Hence, you can always hang a plastic bag with water to drive away flies in your house this way.