Crystal is very delicate, owing to the lead oxides used to make it dense and sparkly. The very lead oxide that makes your crystal reflective, causes the glass to be softer, and prone to scratches.
Crystal should be hand washed, using warm (not hot) water to wash and rinse, as it is sensitive to temperature changes.
If you have cloudy crystal, I would first try a small amount of plain old white vinegar, diluted a bit with water, on a very soft cloth. (A very well used cloth baby nappy of the flannelette kind would be perfect, or an old, thin tee shirt). Wipe the cloudy area gently, and rinse immediately with tepid water, not cold.
If the glasses are gold-rimmed, take care not to get vinegar on the rims.
If you notice that your crystal has a haze or clouding look to it and are having trouble removing it, you need to move to the next level and try cleaning with a hard water stain remover such as CLR or Lime Away. Some people have even used #000 very fine steel wool with a mild dish detergent to remove stubborn haze. But I wouldn’t resort to the steel wool unless none of the other solutions worked and you are willing to make the problem worse!
If ordinary vinegar doesn’t do the trick, Planet Natural has a non-toxic lime removal product, called Lime Eater. Removes lime and calcium buildup, soap scum, water spots and rust without fumes or harsh mineral acids. Great for cleaning showers, tubs, sinks, fixtures and glass soiled by frequent contact with water. Natural lime scent.
Cloudy glass is called ‘Sick glass’ and denture tablets may be able to clean them. Fill a basin with water then add four denture tablets and let glasses stand until the cloudiness disappears.
Try a mixture of lemon juice and carb soda, or a mixture of lemon juice and vinegar, brushing with a very soft toothbrush.
If you live in an area with a high water calcium, you might have other calcium/lime build-ups such as on your cutlery, coffee plunger or kettles.
This method serves two purposes by cleaning out the dishwasher and removing the white mineral residue from glassware. Put all of your glassware into the dishwasher and place a bowl with 1-1/2 cups of liquid chlorine bleach in the bottom. Do not add dishwasher detergent. Run the dishwasher through the wash and rinse cycles but not the dry cycle. Next, empty the bowl and add 1-1/2 cups of white vinegar and run the dishwasher through the wash, rinse and dry cycles. If you have a heavy mineral buildup, you may need to do this a few times, then keep it up with a monthly or bi-monthly cleaning, depending upon what best suits your needs.
DO NOT PUT SILVERWARE IN WITH THIS WASH as the chemicals will strip off the plating.
If you have broken crystal stemware and it still has a bit of a bell shape, do as I did and drill a hole (with a Dremel diamond drill) through where the stem should be and add some old guitar strings and large beads and make a wind chime!