If your bathroom or basement has a musty odor, chances are you have a mold problem. Mold can grow inside ductwork, behind walls and ceilings, and under floors—anywhere excessive moisture builds up. Although mold can typically be detected by smell, you also can check by shining a bright light on any suspect areas or using a black light. Fortunately, this home irritant can be easily removed with commercial cleansers. Prevent future buildups of mold by using dehumidifiers and fans to reduce dampness.