Leather, like any type of animal skin, not only dries out over time without moisturising treatments, but also quickly absorbs liquids that come in contact with it---including felt tip pen ink. Since leather is delicate, it is important to use care when removing ink, as a leather item's surface or finish can break down if cleaned improperly. To remove felt tip pen ink requires that you use a cleaning product specially formulated for the type of leather that you're trying to clean.
Sprinkle corn meal onto the fresh ink stain to absorb the excess before it spreads. Wait 15 to 25 minutes and then carefully dry vacuum the corn meal from the leather surface. This will not work on a dry stain.
Apply a professional leather cleaning product to the stain. Apply a leather stain remover or leather cleaner made specifically for the type of leather that you're trying to clean. Follow the instructions outlined on the package for the product that you choose.
Blot the stain gently with rubbing alcohol (70 per cent solution) on a white, lint-free cloth or cotton swab if the cleaning product doesn't work. Repeat with the alcohol and fresh cloths or swabs as needed until the ink completely transfers from the leather.
Wipe a leather restorer across the previously stained area to remoisturize, protect and/or refinish your leather.
Test a professional leather cleaning product on an inconspicuous area of your leather item before use to protect against staining. Always contact the manufacturer of your leather item to confirm that it doesn't require a special cleaning method.
Never remove felt tip pen ink from leather using abrasive, harsh chemicals or cleaners as they can break down the leather, removing a surface layer or causing it to dry out or crack. In addition, these cleaners can damage finishes---remove protective coatings or fade dyes. Never rub at the felt tip pen ink stain on your leather as friction can remove a top layer (leather or finish) or cause other types of damage including stretching. In addition, rubbing can push a stain into unstained areas.