Check closed boxes and other dark storage areas for mold and mildew. If something smells musty, molds and mildews are present. Place musty smelling items outside in direct sunlight. For the sake of your health, do not use a flood soaked room or wet, moldy basement for sleeping or general living activities until mold spores are under control. Mildew is a thin, usually black, sometimes white, growth produced on many kinds of surfaces by molds.
Molds are very tiny microscopic plants.
Mold spores are so tiny that even small movements of air will circulate them to all sections of a house. Though molds are always present in the air, those that cause mildew grow best in cool, dark, moist places. These molds will grow on anything from which they can get enough food. In flooded basements and houses, molds will develop most often on draperies, carpeting, upholstery and mattresses, natural fiber clothing, leather shoes and gloves, paper and books, cardboard boxes and even on artificial Christmas trees. As molds grow, they cause considerable damage.