Removing Scratches on Colored Glass Plates?

I'm an artist and I paint on colored glass plates. It is very hard to find new plates as there are not very many companies making colored glass plates these days. So I'm stuck buying used/vintage ones and most have scratches from utensils. I can't find any great source directed to colored glass plates only other types of plates and don't know if they would work. I hope someone can help me :)