To eliminate flies, first aim to eliminate their sources by removing foods and materials on which flies can lay their eggs. Clean up dumpsters and garbage cans, and ensure their lids remain closed always. Make sure that all drains are flowing smoothly to get rid of extra moisture. Shut all openings to the building, and if the weather is too hot, invest is some window guards and screen doors.
Kill all flies inside the house using insecticides that come in residential forms, such as baiting forms, aerosols and dust forms. Disposable and electric fly traps are also efficient and functional. Granule fly baits are used along walls and window sills inside the building and in areas outside where flies congregate.
Insecticide aerosols contain pyrethrins to work quickly but give no lasting residual. Sprinkle insecticide dusts in all cracks and crevices. The dust flows into the void areas and kill hiding flies. For maximum results, use pesticides during the day.
After killing inside flies, kill flies outside, and take the necessary preventative measures. Hang sticky fly strips in areas where flies congregate in large numbers, such as sheds and porches. Use Venus fly traps for areas where flies tend to land a lot. If the above control methods do not work, contact an experienced exterminator for assistance.