We have a beautiful Indian Peacock slate corridor in the school I'm at. Over time the sealer has worn away in some places and underneath is dull and lacks the original pattern.
I wonder if it might be possible to "touch up" that slate which has been revealed - we tried different shades of shoe polish, that did not work. It wouldn't stick to the slate. But what about oil paints or something else.
If we succeed witht the touch up, we will seal it again and it will be good for a few more years.
Mike