Heritage Auctions states that the best way to clean antique glass is by hand with lukewarm water and mild dish washing soap, and then towel drying afterward. Never use hot or cold water, as the temperature change can shatter the glass. Using a dishwasher is a risky method that is not recommended, as the vibration can shatter the glass.Know More
Heritage Auctions further explains that normal dirt is not the only factor that can ruin the appearance of antique glass. Glass can also suffer from mineral buildup that gives it a dull, cloudy appearance. There are several ways to remove this foggy appearance.
In all cases, if water is used, ensure it is of moderate temperature. If the object is a container, it can be filled with a mix of water and ammonia for a few hours, which should dissolve the offending deposits. Instead of an ammonia mixture, the object can be filled with water with a denture cleaning tablet added. Petroleum jelly removes light calcium deposits when it is applied and left in place for a few days. Some toothpastes also work with removing calcium deposits from glass. Tub and tile cleaners are actually designed for the same sort of mineral removal, and work on glassware, as well.