8 Things You Should Never Put in the Dishwasher — and Why
The dishwasher is convenient, but high heat, strong detergents, and powerful water jets can damage certain kitchen items. Always check the manufacturer’s instructions when you’re unsure.
1. Wooden Cutting Boards and Utensils
Hot water and prolonged moisture can cause wood to swell, warp, crack, or split. Hand-washing and drying wooden items promptly usually helps them last longer.
2. Cast-Iron Cookware
Dishwasher detergent and prolonged exposure to water can strip away the protective seasoning and encourage rust. Cast iron is generally better cleaned by hand and dried thoroughly.
3. Sharp Kitchen Knives
Repeated dishwasher cycles can dull knife edges. The blades may also knock against other items or become damaged. Hand-washing and drying sharp knives is usually preferable.
4. Nonstick Cookware
Strong detergents, high temperatures, and repeated washing can gradually wear down some nonstick coatings. Unless the manufacturer specifically says the cookware is dishwasher-safe, wash it by hand.
5. Copper Cookware
Dishwasher detergents can cause copper to lose its shine and develop discoloration. Hand-washing is generally the safer choice for maintaining its appearance.
6. Crystal or Delicate Glassware
Heat and strong water jets can cause delicate glass or crystal to become cloudy, scratched, chipped, or even cracked. Hand-washing is often recommended for valuable or especially delicate pieces.
7. Insulated Travel Mugs and Vacuum Bottles
Some insulated containers have seals, valves, or vacuum insulation that can be damaged by dishwasher heat. Water can also become trapped inside certain components. Check the manufacturer’s care instructions.
8. Items With Decorative or Painted Finishes
Gold rims, hand-painted designs, decals, and decorative coatings can fade, peel, or wear away during repeated dishwasher cycles. These pieces are generally safer when washed gently by hand.
A Simple Rule to Remember
If an item is made from wood, cast iron, delicate glass, copper, or has a special coating or decorative finish, don’t automatically assume it belongs in the dishwasher.
Bottom line: Before putting an unfamiliar item into the dishwasher, check for a dishwasher-safe label or the manufacturer’s care instructions. A few extra minutes of gentle hand-washing can prevent expensive kitchenware from being damaged.
