To remove stains on a porcelain sink, make this simple cleaner to use at home.
1 tsp. liquid dish washing detergent
1/2 cup liquid chlorine bleach
1/2 cup white vinegar
Close the drain and fill the porcelain sink with 3-4 inches of warm water. Add stain remover solution and gently mix with water. Leave mixture in sink overnight or for the day (about 8-12 hours). Drain and rinse with hot water.