Dishwasher Detergents and Glassware

Dishwasher detergents are not kind to 19th-century pressed glass and other old glassware. We were using some Moon & Star pattern sauce dishes and noticed that a few are showing wear on the flat part of the bottom. The worn areas are not scratches, but seem to be rough spots on the original sheen. Now the bottoms look dull. We blame the dishwasher.