Also a well known way to clean old glass like old soda pop bottles is to use a tumbler or ball mill without the balls and use sand in place of balls. You can do just the inside of them too, they come out like new. More useful for hard to get at places as it may take 2 days to get it all clean. By the way, if all you have is a steel ball mill, you will have to put the glass inside a plastic container then place that in your ball mill.