Aluminum: It’s usually dishwasher-safe, but minerals in the water might cause spots or darkening. If you want to remove those, scour with a soap-filled steel wool pad.
China, crystal, and stoneware: It’s mostly safe, but if the pieces are hand-painted or fragile, wash by hand. And if it has gold leaf, that might discolor or fade in the dishwasher, then hand-wash, Larry says.
Glass: Milk glass material might yellow after repeated washings in the dishwasher.
Plastic: Plastic items vary in their ability to withstand heat and detergents, so check whether it’s dishwasher-safe and make sure to place it on the top rack—away from the heating element—and don’t select cycles that use higher wash or dry temperatures.
Stainless steel and silver: They’re generally safe, but make sure you run your rinse cycle if not washing immediately because prolonged contact with food might damage their finish.
