When crystal begins to exhibit a cloudy or foggy appearance, it is important to act fast to remedy the problem and prevent permanent damage. This clouding is either a film build-up on the crystal or etching. While you can remove the film from your crystal with simple cleaning techniques, etching is a permanent problem. If you notice spots or film on your crystal glassware, start treating the problem immediately to avoid permanent damage.
Scrape the at the cloudy part of the crystal gently with a pin. If you can scratch away the cloudiness, it is film and you can remove it. If the pin has no effect, your crystal is probably etched and you cannot remove the cloudy effect.
Wet a dishcloth with white vinegar.
Wipe the cloudy crystal with the vinegar soaked dishcloth to remove the film completely. Remember to clean the inside and outside of the glassware to ensure that all of the film is gone.
Hand wash the crystal glassware in warm, soapy water to remove all of the vinegar.
Dry your crystal glassware gently with a soft, lint-free cloth.
The high temperatures of your dishwasher can cause etching. Hand wash your crystal glassware to avoid this problem.