I'd like to praise you are absolutely fantastic Weiman glass cooktop cleaner. I've been using your product for quite some time and decided to try it on my expensive porcelain kitchen sink. It had a number of marks on it from aluminum and iron skillets. I had tried repeatedly to rub them out using substantial elbow grease using products like "Bon Ami"& "Bartender's Friend" with no luck. Anyway I had ran out of nonabrasive cleanser and decided to use your product that I normally use on my glass cooktop stove. And to my surprise it removed all of the aluminum and cast-iron marks on my porcelain sink! I couldn't believe the difference it made! It made it look brand-new again!