Apply this solution to the outside of the shoes, and gently scrub with a clean brush or cloth. Mix a small amount of mild detergent with water in another bowl. You could also use a store-bought ...
If necessary, follow up by scrubbing hard with a white eraser. You can also use a nail file. For truly stubborn stains, use a white washcloth to rub white vinegar or rubbing alcohol to attack the spot ...