There should be a "scraper" for this call that has two different types of sanding surfaces. I had to buy it seperately. It is made out of black plastic, about 8 inches long, and has a cresent type shape at each end of it. One end is for glass, and the other end is for ceramic. I had a heck of a time sanding the ceramic "dome" without it. Check out their site to see if they still make it, or call the company direct. I am sorry I do not have their information handy.