Removing rust stain from porcelain or ceramic?

Question

I have a couple coffee cups that have rust stains on them, and it seems to be under the glaze. When they were new they didn't have it but they sat in the sink for a couple of days with a metal object that rusted, and I can't get the stain of now. I have tried CLR. It didn't work. Also I have tried rubbing it with baking soda. Anything else I can try to get it off? Or is it permanent now?

Answer 1

You might try OxyClean on them.  If it has made it through the glaze, then the stain is probably permanent.  I like to use CLR on my when I have lime build up in the cups.  Removes the calcium really easy.  Then if I have multiple cups that way I just pour the water/CLR mix into the next cup and keep re-using it multiple times until it loses it's effectiveness.