Don't put crystal in the dishwasher as glasses can knock together and detergents can be quite abrasive. Instead, wash by hand in warm, not hot, soapy water, rinse and dry with a soft, lint-free cloth.
Always hold the glass by the bowl when cleaning, rather than by the stem.
Remove stains from the inside of a decanter with vinegar and uncooked rice. Let the solution soak, then agitate to allow the rice to remove the stain. Alternatively, denture-cleaning tablets work well!
Stand glasses upright, never on the rims – the rim is the most fragile part of the glass.