Pen ink is intended to be permanent, creating a worry that if it drips or explodes on to your nylon or polyester coat, the coat is doomed. Both nylon and polyester are synthetic fabrics that are durable, but will shrink and deform if laundered improperly. Save your durable nylon or polyester coat from a permanent spot in the back of your closet by removing the pen ink stain without damaging or warping either fabric.
Saturate the stain with glycerin. Work the glycerin into the stain with a soft-bristled toothbrush. Continue to cover the stain with glycerin and scrub it with the toothbrush. Rinse out the glycerin under a cool tap of running water.
Examine the stain and if it persists, create a mixture of 1/4 cup liquid laundry soap and 5 to 10 drops of ammonia. Dampen a white washcloth with the mixture and dab at the stain. Continue to dab at the stain until it's completely eliminated. Rinse out the mixture under a cool tap of running water. If the stain persists, move to the next step.
Dab at the stain with a washcloth dampened with dry-cleaning solution. Continue to dab at the stain until it's completely eliminated.
Rinse the garment under a cool tap and launder according to the garment's care label. Don't wash a nylon or polyester garment in hot water, which can cause permanent wrinkling and damage.