Leather is a luxurious material, which makes it an expensive investment. While certain stains may require a redying of the leather, others--such as ballpoint pen marks--can usually be removed at home. This depends on the condition of the leather prior to the incident, which is why you should always do a spot test to determine colour fastness. When in doubt, contact a professional cleaner, as it is possible to permanently damage your treasured leather items.
Soak a cotton swab in rubbing alcohol.
Rub the wet cotton swab on an inconspicuous area of the leather to verify that it won't change the colour of the leather. If the leather isn't negatively affected, proceed to the next step.
Scrub the ballpoint pen marks with the wet cotton swab, covering the entire area. Do not allow the alcohol to dry. The stains should go away immediately.
Dampen a clean towel with water, and use it to rinse the entire affected area. Dry the area with a fresh, dry towel.
Rub a small amount of leather conditioner into the freshly cleaned area with a dry towel to prevent the leather from drying out from the use of alcohol and water.