Waterproof mascara is designed to remain on your lashes through rain or tears, but the waterproofing capabilities make this particular type of mascara difficult to remove if it stains one of your shirts. Unlike water-soluble mascaras, waterproof mascara is made with water-repelling, oil-based ingredients like isododecane that give the mascara its staying power. When you're treating a shirt that's been stained with waterproof mascara, you'll need to treat the stain with a nonaqueous combination solvent that is able to break down the oil and lift the stain from the fabric.
Remove as much of the dried, flaked mascara as possible with a pair of tweezers. Lift the pieces directly up off the shirt to avoid causing additional smudging and staining.
Apply a small amount of dry cleaner fluid or powder to the stained area. Dry cleaning chemicals are oil solvents that break down the oil-based elements of the mascara to remove the stain. Allow the chemicals to set or dry per the manufacturer instructions.
Blot the chemicals off of the fabric with a clean sponge or cloth. Do not rub the stain, which will only spread the mascara around on the shirt.
Treat the stain with a fabric spot cleaning detergent. Work the detergent into the stain well enough to form a lather. Rinse the stain with lukewarm water.
Prepare a solution of equal parts ammonia and lukewarm water. Apply a small amount of the diluted ammonia solution with a plastic syringe or eyedropper to the mascara stain to remove any remaining smudge marks. Blot or press the stain with a clean cloth. Rinse the ammonia away with cool water.
Launder the shirt as you normally would in your washing machine.