Polyurethane is a material made with a combination of polymers and organic materials and is often used in fabric or on foam surfaces. Spandex clothing, upholstery and mattresses are a just few of the items for which polyurethane is used. When pen marks end up on a polyurethane surface, it should be treated the same way in which you would treat other synthetic fabric surfaces that have been stained with pen. By treating the surface properly to remove the pen, you can do so without damaging the item.
Dampen a clean cloth with dry cleaning solvent. Lay the pen ink-stained polyurethane on a flat surface. Sponge the ink stain, starting at the perimeter and working your way in, with the dry cleaning solvent to loosen and lift the stain. Avoid the temptation to scrub the stain as this can cause it to spread and damage the polyurethane fibers.
Place a few drops of liquid laundry detergent on a damp cloth. Blot the ink stain with the detergent to cleanse the fabric and help remove ink loosened by the dry cleaning solvent.
Rinse the detergent off the polyurethane by dabbing the site of the stain with a damp cloth. Repeatedly blot the fabric until the detergent is gone.
Treat any remaining pen mark stains with a paste made of two parts oxygen bleach to one part water. Mix the two ingredients together in a bowl then rub into the ink stain. Allow the paste to remain on the polyurethane for 10 minutes.
Fill a bucket with warm water and add 1 tbsp. laundry detergent. Dunk the polyurethane fabric in and out of the water to agitate. Allow the fabric to soak in the soap solution for 10 to 15 minutes. Rinse the garment under warm running water to remove the detergent and wash out the remaining ink stain.
Allow the garment to drip dry outside, away from direct sunlight, or over the bathtub.