Ink pens are well known for breaking and leaking onto clothes and upholstery and creating quite a mess. Perhaps you had a pen stowed in your trousers pocket and broke it when you sat down, creating a mess on your car seat. While these type of stains are best dealt with when fresh, in many instances you can successfully remove even an old stain with a bit of effort and the right cleaning products.
Dampen a non-abrasive sponge in cool water and wipe the ink-stained area. Add a drop of mild liquid dish detergent to a small dish containing 236ml. of clean, cool water.
Dip the sponge in the soap and water solution and sponge the ink stain. Rinse out the sponge in clean water and sponge water onto the stain to rinse.
Blot dry with a clean towel.
Pour one to capfuls of undiluted isopropyl into a small bowl and dip a section of clean, white towel in the alcohol.
Blot the ink stain with the alcohol soaked section of the towel from the outside edges to the centre to clean.
Blot the stain thoroughly with a dry portion of the towel to keep the stain from spreading.
Acetone or turpentine can be substituted for the rubbing alcohol in Section 2.
If you are using anything other than soap or water, ensure that the chemical is safe to use on your car seat fabric. Apply a small amount of the chemical or solvent to an inconspicuous area of the fabric and blot with a clean white towel. If you see any fabric dye transfer on the towel, you shouldn't use the solvent as it may damage your seats.