Insecticide sprays and powders are efficient at getting rid of cluster flies. Using a mini-vac has also been proven to help get rid of these flies.
There are two main types of insecticide products that work well for exterminating cluster flies, including aerosol sprays and dusts. Insecticide dust is used when the flies are coming from cracks and crevices in the walls or floor. The dust spreads around in the different cracks, successfully treating the problem areas. The sprays are useful for killing the flies directly on contact. This requires spraying the flies directly, so it might not solve the problem completely. Be careful when using aerosol insecticides inside the house.
Insecticide concentrates are also available, which are applied to the perimeter around the home, on the walls or on the floors. They can be stronger than sprays or dusts but can sometimes leave behind residue. Some concentrates are also odorless, which is good for interior use.
An important aspect to treating a home for cluster flies is working to prevent them in the future. After getting rid of them successfully, keep treating the perimeter of the home with the preferred type of insecticide. Keep all trash covered and clean up messes inside the home regularly.