Etching is a permanent condition that is irreversible, according to Good Housekeeping. Many times glassware develops a cloudy appearance in the dishwasher. Soaking glasses for 15-minutes in undiluted vinegar normally removes any cloudy film. If vinegar does not dissolve the film, etching is the likely cause.
One of the most common causes of etching is using too much dishwasher detergent with soft water. Detergents containing phosphates are more likely to cause a problem. The University of Nebraska-Lincoln recommends adjusting the amount of detergent used depending on the hardness of the water. With extremely hard water, it recommends filling both dispenser cups completely and operating the machine on its low energy cycle.
Prewashing or rinsing the dishes before placing in the dishwasher is unnecessary. The machine works best when the person loading the machine scrapes excess food away and loads the dishes directly into the machine. When dishes are too clean at the beginning of the cycle, the chemicals in the detergent do not dilute properly and the chances of permanent etching increases.
Hand-washing special glassware or crystal eliminates the potential for permanent etching. Once washed, drying with a soft cloth helps to prevent the formation of water spots that form from air drying, especially in areas where hard water is a problem