When you want to work on spots like mineral deposits or rust, you can sometimes use mild abrasives on glass without damaging it. Always test the technique you're using in an inconspicuous area, like the bottom of a tumbler, before you tackle the spot itself. If you're determined to lose the spots, one of these methods may be worth a try. Be very cautious when using them, and weigh the advantages of possibly removing a blemish at the risk of making the whole project look worse than when you started.
- For stubborn spots, scrub with a stiff artist's brush or soft toothbrush. (Choose an inconspicuous area for a preliminary test.)
- Try a dab of baking soda or toothpaste on a soft cloth.
- Use polish especially designed for glass-topped stoves.
- Try window polishing cream.
- For rust, rub the spot with a copper pad and wipe with water. (Make sure the pad is really copper, and use light pressure.)
- Use scouring powder applied with a bottle brush to remove the dried gunk on the interior of bottles and vases.
- To clean the interior of a narrow vase, use an oxygen cleanser, or try equal parts baking soda, vinegar and salt.