While many of your plates, bowls, cups, and mugs are likely dishwasher-safe, there are some items you should avoid putting in the dishwasher. This includes anything made of cast iron, pots or pans with a non-stick coating, expensive knives, and very delicate items. The dishwasher's process can harm these items and materials, and even break them or reduce their quality. Wash these items by hand instead, making sure to follow our guides on how to clean cast iron and how to clean ceramic pans and cookware.