If your jacket is suede or nubuck, you should take it to a Leather Jacket Cleaning. Check labels to determine what material the liner is made of. Despite what you read on the internet, a leather jacket should never be fully submerged or thrown in the washing machine.
Regular maintenance and wiping with a damp cloth will prevent dirt and oil build-up, and storing the jacket in a dry place will prevent mold growth. The Best Dry Cleaner suggests using a damp cloth and soapy water to remove any dirt, oil, or light stains. Press gently without rubbing to avoid getting your skin wet.