Jeweler's rouge or a very fine polishing compound like chrome polish should work.
I can tell you from experience that jewelers rouge does not work on glass. Some places are advertising systems that are supposed to work and I'd like to hear from someone who's used one of them.
Here's an interesting bit of trivia... Did you know that glass is a liquid? It's true. You can hang a weighted piece of wire over the edge of glass and over time the wire will cut through the glass.
