Soak a cotton ball with paint thinner designed for use with solved-based paints.
Lay the piece of clothing onto a pile of newspaper. The newspaper will soak up any paint-thinner that leaks through the clothing.
Blot at the stain with the cotton ball. The paint thinner will begin to remove the solvent-based industrial marking paint from the piece.
Rinse the paint thinner from the clothing with plain water.
Pour 1 tbsp. heavy duty liquid laundry detergent onto the affected area. Work the laundry soap into the stain with your fingers. The laundry soap will not only remove any remaining paint residue it will also help eliminate some of paint thinner odor.
Launder the clothing according to the label's directions.
Inspect the item after removing it from the washer. If the paint is removed, dry the item. If the stain persists, repeat cleaning the piece with paint thinner.