Dishwashers are wonderful, time saving devices but unfortunately do no favours at all to precious glassware. If you find that your glasses are losing their sparkle and becoming cloudy it may well be because of the action of the dishwasher – a combination of the softeners that are put into many water supplies, coupled with the high temperatures and the detergent we use in the dishwasher.
Delicate crystal or precious glassware is therefore best cleaned by hand. If you don’t want to tackle the washing up straight after you’ve used your glasses, do at least give them a quick rinse so that wine or other liquids aren’t sitting in them for any length of time. Wash individually in hot soapy water – ordinary washing up liquid will do – and then rinse straight away in hot clear water. (Don’t rinse in cold water because the change in temperature may make the glass shatter). Place on a draining rack and then dry with a lint free cloth. (I usually dry with kitchen roll and then shine with a lint free cloth).
If you have items like narrow vases that are difficult to clean, use denture cleaning tablets to do the work for you but only leave for the recommended length of time. Rinse and then dry.
Glassware that has a cloudy or milky appearance may be restored to a sparkle by wiping gently with vinegar on a soft cloth. However, it’s worth saying that liquids can actually permanently etch the surface of glass, giving that same milky appearance.
The moral of the story is simple: Never leave liquids sitting in glassware for any length of time.