We removed metal marks off our walls really easily with the Mr. Clean
magic eraser. I was really surprised how well it worked.

Chris J... wrote:

I've got white ceramic tile in my kitchen, and recently
some relatives with young children came to stay for a short visit.
I tried to "child proof" and put any potential dangers out of reach,
but being a non-parent and not good around kids I didn't foresee all
risks. The kids (age six and eight) found my snow cleats (pointed
steel cleats I strap on my shoes for working in snow and ice) and
decided that ceramic tile made a fun substitute for ice. Result? a few
chipped tiles and a whole bunch of long shiney metal marks all over
the tiles.

Replacing them was not an option; they match other tiled areas
throughout the house (bathrooms, utility room, laundry room) and I
can't find replacements (they are no longer made). The chips aren't
bad (I found the pieces and superglued them back) but the metal marks
were unsightly and wouldn't come off with normal cleaners or
lime-away, or even muriatic acid. I even tried pencil erasers, no
luck, and google searches turned up nothing that worked.

But, I recently tried a product for removing toilet bowl rings, a type
of abrasive cloth called "miracle cloth". It worked great, and on a
whim I tried it on the metal marks. It took one heck of a lot of elbow
grease, and resulted in a slight dimming of the glaze, but it worked.
So, I thought I'd post this here for anyone else who has this problem.

It also worked well for removing silicone "aquarium" sealant that
those kids also tracked over my tile and I didn't discover until it
had set. A razor blade left a bit behind, but the cloth plus elbow
grease cleaned it off. Now, if only I could figure out how to get that
stuff out of carpet...

Chris.