Cleaning mold off leather is easy, using glycerin soap and warm water and a soft rag. Wipe off excess soap with a dry rag, then hang item out in the sun if it's a nice day, or put in the dryer on high heat for 3-5 minutes.
Leather clothing, shoes, handbags, etc. can develop mildew while being stored. One method that can be successful is wiping down the item with white vinegar. No matter what you use, be sure to check colorfastness before cleaning the entire surface. This is a page about removing mildew from leather.
