Porcelain is a strong, water-proof surface that is non-absorbent and sleek. The non-porous exterior makes it resistant to stains and odors; however, daily upkeep will keep white porcelain sinks glossy and beautiful for decades to come.
For everyday use and to remove stains, use a mild abrasive cleaner and a sponge or soft cloth. After cleaning and drying the porcelain sink, consider using lemon oil as a finishing polish. In addition to restoring the sheen to the porcelain surface, it also creates a protective barrier to further prevent stains.
If you have scuffs and scratches, use baking soda and water to form a paste. With a sponge, work the mixture in a circular motion over the scuffs or scratches, and rinse with water. In addition, many porcelain sinks for kitchen use suffer scuffs and metal marks from pots, pans and utensils. A product called Naval Jelly, which is sold at most hardware stores, effectively removes metal scratches and rust stains.