Mechanical exclusion can help to get rid of cluster flies. Many homeowners use physical barriers to repel a variety of common insects. Homeowners can seal cracks around utility pipes, siding, doors and windows. Applying screens that are made of vine mesh can help. An indoor infestation of cluster flies can potentially be controlled with specific insecticides.
Many homeowners choose to use a powerful fogger that is capable of controlling these insects. However, it's almost always a better idea to contact professional pest control experts.