The tiled window sill on the front of our house had been painted years ago
and the paint was peeling off.

So although a long job I patiently scraped off all the paint. Then
discovered that a couple had been damaged and just filled with a filler and
painted over.

I'm in the process of removing one. See web pictu

http://tinypic.com/view.php?pic=2rg1jd2&s=5

Stupidly I thought they would clean up well with a carborundum stone, but
soon realized that they were *glazed* and I have now made a right mess of a
couple of them. See the two to the right of the broken tile that I'm in
the process of taking out.

I really don't want to paint them again unless I have to, since I 've a
feeling its just going to peel again in a couple of years. Any suggestions
as to what I'm best doing to try and repair scratched tiles?