I need information about how to easily repair dings on the porcelain finish of a kitchen sink. It is a relatively old sink, in case this makes any difference in the repair application.
By K.I.D.
I assume you mean dings in the finish revealing the black cast iron underneath. You can do it with touch up paint that many kitchen stores sell in a variety of colors.
Using an abrasive scrubbing sponge can leave scratches on a sink. Check with your local hardware store to see if there is a product or procedure for repairing the damage. This is a page about scratches on a porcelain sink.
