Always hand wash carefully in warm soapy water, preferably in a plastic basin.
For stubborn water marks soak in warm white vinegar for a few minutes before washing.
Always rinse soap off with clean warm water.
Always dry with lint free cloth.
Never wash in the dishwasher.
Never use very cold or very hot water.
Remember good crystal can be sensitive to sudden changes in temperature, so keep in mind when you are displaying/storing your crystal.
Always be careful handling your crystal.