My glass class has lost a lot of its surface. I have tried a coarse grit sand paper, but it just doesn't put the surface back on the call.Does anyone have any experience in re-conditioning a glass surface i.e. what to use, what not to use, what method for re-conditioning etc. I have been trying to see if there is some sort of diamond surface sandpaper available, but have not seen it on the internet. If you know of a product I might be able to pick up at a big box home improvement store, I would appreciate it very much.