Expert: George Maxwell - 9/8/2007

Question
I had a plumber work on my kitchen sink faucet/spigot (small leak).  He used Hydrochloric Acid to remove the lime crustrations.  When he finished, my stainless steel sink was left with some round spots which are dark on the outside, and lighter, inside.  Is there any way to get rid of these acid marks -- or is the damage permanent?

Answer
Thank you for your question.

If the damage has been caused by acid, this means that the material has been attacked and eaten away on the surface, not just stained. You therefore have two options:

If the sink is not highly polished, you could use steel wool to remove the damaged areas. This might cause further damage on polished metal though.

Otherwise, I would recomend using a metal restoring paint (ask at your local hardware store). In our labs, we use Hammerite paint to resurface damaged steel sinks.

If you have problems with limescale build-up again, you might want to use vinegar to remove it: vinegar's a strong enough acid to remove scale, but is less likely to attack steel.

Hope this helps.