Soak a clean cloth in nail polish remover.
Rub the cloth over the nail polish stain on the porcelain. Work from the edges of the stain toward the center and rub until the stain is gone.
Immediately mix ¼ cup trisodium phosphate with 1 quart water. Mix until the trisodium phosphate completely dissolves.
Dip a cloth into the solution and rub it over the stain to neutralize the nail polish remover. This will prevent the chemical solution from sitting on the porcelain for too long and damaging it.
Rinse the porcelain with clear water and dry it completely with a clean cloth.