This is the cure for dirty sock syndrome. Air ducts are often the source of odors, caused by smoke, pets, cooking, spoilage and other agents. FreshDuct Odor Eliminator is specially formulated to control odors gently, but effectively. If you have an odor from mold in air handlers, ductwork, or coils, then this is a great product for you. Its non-toxic, biodegradable formula encapsulates and destroys odor-causing molecules on contact, while time releasing a fresh fragrance - freshening and deodorizing the interiors of both, lined and unlined ducts.