Mildew is a type of mold that occurs in warm, damp environments. It is usually black or white with a thin texture, and produces a distinctive sour odor. When mildew grows on fabric, it can cause discolored stains that can be difficult to remove. Natural fabrics like leather are more likely to have mildew problems than synthetic fabrics, according to the University of Missouri. You don’t have to throw valuable leather items away if they become infested with mildew. If you use the proper technique, you can remove the mildew without damaging your leather.
Add 1 cup denatured alcohol and 1 cup of water to a glass bowl and stir with a spoon to evenly combine the mixture. Place a cotton cloth directly into the alcohol-and-water mixture so the cloth is thoroughly dampened.
Squeeze the cotton cloth lightly to wring out any excess liquid. Apply the damp cloth directly onto the mildew stains and scrub the leather gently until the mildew stain is no longer visible.
Store the leather item in a spacious area with access to airflow, such as near windows or vents. Allow the leather to dry completely before you handle it.
Examine the leather once it has dried to determine if any mildew is still present. Add soap and warm water to a container and mix it to form a lather, then use a cotton cloth to scrub at any remaining mildew.
Dampen another cotton cloth with clean, warm water and apply it to the soapy areas of the leather. Wipe the soap with the damp cloth until all of it is gone, then move the item back to its drying area and let it air dry. Inspect the leather after it has dried to ensure all the mildew is gone--if not, consult a leather goods store to see if they offer professional cleaning services.