Flies can be a tremendous irritant, but the chemical sprays used to repel them can be just as irritating to your respiratory system. Keep flies away using natural spices that are pleasing to or unnoticed by humans in order to avoid breathing in harsh chemicals. Spices can be used as sachets or in their live, planted form to repel flies.
The easiest way to use cloves to repel flies is to tie bundles of cheesecloth with several handfuls of cloves inside. Then hang the bundles near doors or windows. Flies do not like the scent of clove oil and will avoid the area. For campgrounds or when grilling outside, sprinkle ground cloves into a small pot of water and allow it to simmer over the fire. Replenish the water as it evaporates, and add more ground cloves as needed.
Flies also do not like the scent of black pepper oil and will avoid strong pepper smells. An easy way to use black pepper is to mix an egg yolk with 1 tablespoon each of molasses and black pepper in a small dish. Place the dishes anywhere you want to repel flies and replace the contents when they dry.
Mint can be used either dried or fresh to repel flies. As with cloves, you can make bundles of mint to hang near doors and windows. You can also use cut mint by keeping it in fresh water and placing it on tables or window sills. Plant mint near your doors to keep flies from flying into the house. Mint grows well in containers, window boxes or in your garden.
Dried or fresh basil works equally well to repel flies. Make cheesecloth bundles to hang, or use potted basil on tabletops or window sills. If you water basil from the bottom of its pot, it produces a stronger odor and will do an even better job repelling flies. Plant basil in outdoor window boxes or alongside mint near the doorway to supplement mint's fly-repellent abilities.