Remember to ALWAYS test a small, hidden area of the furniture first before using any of these methods.
Ink stains: Dip a cotton swab in rubbing (Isoprophl) alcohol and rub over the ink stain. Dry with a blow dryer set on its lowest setting.
Dark stains: (i.e. food, blood, etc.): Make a paste of one part cream of tartar with 1 part lemon juice. Rub this paste on the stain and leave it set for 10 minutes. Remove the paste with a damp rag and moisturizing soap, as described above for general cleaning. Buff the leather dry with a soft cloth.
Grease stains: Simply wipe stain from the leather using a dry cloth. Do not apply water to the grease stain.
Newsprint: Newspapers left on leather furniture can cause a newsprint ink stain. Spray the stain lightly with aerosol hair spray and then wipe with a soft cloth.
*** NEVER use any kind of oils (such as mink oil), furniture polish, or any product containing waxes or silicone (including many car care products) on your leather furniture as it may damage the leather.
*** Never use varnish, ammonia-based cleaners (i.e. Windex) or bleach on your leather furniture, all of which may be too harsh for the leather and may cause serious damage or discoloration.