Cream of Tartar - Long-forgotten cleaning agent gem may be used with a little water or vinegar to lift even the most stubborn stains. Use on grout, mold and mildew stains, burner pans and casserole dishes. Cream of Tartar is your new best friend.
For cleaning? I tried it, as this advises, w/ a little vinegar, for my oven glass, and it did absolutely nothing. Use some soapy water and the kind of blade one uses for scraping paint off a window (carefully).