Remove mold from leather by drying the leather item, removing any surface mold, drying the leather item again and cleaning the leather thoroughly with an appropriate cleaning solution. Do not store the item in a dark, humid location, as this encourages mold growth.
Dry the leather before cleaning by leaving it in a warm room. When it is thoroughly dry, remove surface mold by wiping it with a damp cloth or brushing it with a soft bristle brush. Do all the cleaning outside, if possible, so that mold particles can disperse. If cleaning must be done indoors, vacuum the leather with a soft brush attachment. Then allow the leather to dry for the second time.
When it is completely dry, clean the leather with a specialized leather cleaner, germicidal soap or another type of very mild soap. If using germicidal soap, create suds by mixing a little of the soap with water in a bucket. Spread the suds over the leather with a lightly damp cloth, and wipe them away with a clean damp cloth. Cleaning the entire leather item enables even texture and color to result.
After cleaning, store the leather item in a warm, well-ventilated room until dry. To help prevent mold, apply mildew inhibitor to the leather, condition the item regularly, and store the item properly.