Scaring away flies with water just might be the most eco friendly way to do it, if it really works.
From José de la O:
The use of a plastic bag full of water hanging from the ceiling of several taco kiosks on the streets, is a traditional way to scare flies away in most of the food markets on urban Mexico. The refraction of the water, amplifies the colors and movements for the sensible eyes of a fly reflected on this sphere, scaring it away, making it the perfect sustainable pesticide, on a way that the insect remains harmless and the food is free of flies.
Size: 21 x 12 cm.