Aluminum, including anodized aluminum
China with metallic decoration
Disposable plastics not labeled "dishwasher-safe"
Flatware with bone, plastic, or wood inlays or handles
Many nonstick pots and pans (check manufacturer's instructions first)
Here are a few more dishwasher "don'ts" to remember:
Don't spill dishwasher detergent on flatware; it can cause dark spots.
Don't use detergents containing chlorine, to avoid the release of chlorine fumes in the kitchen while running the dishwasher.
Don't jam too many pieces into the silverware basket overcrowding can cause items to become scratched.
Don't mix sterling or silver-plate and stainless-steel flatware in the dishwasher, even when using the Rinse-Hold cycle. If the metals come in contact with each other, a reaction between the two metals can damage both finishes. (Since most knives, including sterling ones, have stainless-steel blades, keep them away from other silver pieces, too.)
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