Whether it's a family heirloom or a recent purchase, crystal glassware is as delicate as it is beautiful. It cannot stand up to rigorous cleansing. This creates a problem when the glassware is yellowed from stains. To clean yellowing glassware requires starting with mild cleansing and moving on to more intense cleansing afterward.
Clean stains on delicate glassware with an overnight soak. Cheryl Mendelson in her book, "Home Comforts; The Art and Science of Keeping House" recommends using a solution of half white vinegar and half water. Pour it into the glass and allow it to sit overnight.
Pour the solution out in the morning and wash the glass with warm soapy water. Rinse the glass. Dry and buff it with a soft cotton cloth.
Repeat the soak, if the stains are still there, using a dentifrice powder or tablet. Fill the glass with water and add the dentifrice. Allow it to sit overnight. Pour it out in the morning. Wash the glass. Dry and buff it with the cotton cloth.
Clean the stains on the glassware that were not removed with the overnight soaking method. Home Comforts recommends using a lemon; cut a lemon in half, remove any seeds and gently rubbing the cut part of the lemon on the glass. Wash the glass in a mild dishwashing solution and rinse.
Inspect the glass. If the stain is still there, the Ecology Center recommends sprinkling the glass with baking soda and scrubbing with a wet sponge.
Rinse the glass. If there is any baking soda residue left, rinse with cold water and white vinegar. Dry the glass and buff it with a soft cotton cloth.