In order to prevent mold and mildew buildup, insulation must be removed when exposed to water or smoke. Even a small amount of soot buildup can be enough to tarnish your insulation. Removing tarnished insulation could mean preventing yourself from being subjected to bad odors and even in some cases disease. Animal intrusion in the form of bats or squirrels leaving waste in your home or business can lead to Lymphocytic Choriomeningitis.