What Not to Put in the Dishwasher: 12 Items to Always Hand Wash

The dishwasher is one of the most convenient appliances in the kitchen — but it's not for everything. Putting the wrong items in can ruin your cookware, damage your dishes, and even harm the machine itself. Here are 12 things you should never put in the dishwasher, and why.

1. Cast Iron Cookware

Cast iron and dishwashers are mortal enemies. The harsh detergent and prolonged water exposure strip away the seasoning that makes cast iron non-stick and rust-resistant. After one dishwasher cycle, your cast iron can come out rusty and ruined.

Hand wash instead: Rinse with hot water, scrub with a stiff brush, dry immediately, and apply a thin layer of oil.

2. Wooden Items

Wooden cutting boards, spoons, bowls, and utensils will warp, crack, and split in the dishwasher. The combination of heat, water, and detergent breaks down the wood fibers and any finish or oil treatment.

Hand wash instead: Wash with mild soap and warm water, dry immediately, and oil periodically.

3. Non-Stick Pans

Dishwasher detergent is abrasive and the high heat degrades non-stick coatings over time — even on pans labeled "dishwasher safe." Once the coating starts to flake, the pan needs to be replaced.

Hand wash instead: Warm water and a soft sponge. Never use abrasive scrubbers.

4. Copper Cookware and Mugs

Dishwasher detergent reacts with copper, causing it to discolor, tarnish, and lose its shine permanently. Copper mugs, pots, and decorative items should always be hand washed.

Hand wash instead: Mild soap and warm water. Polish with a copper cleaner to restore shine.

5. Crystal Glassware

Fine crystal is too delicate for the dishwasher. The heat and detergent can etch the surface, causing permanent cloudiness. Crystal can also crack from thermal shock.

Hand wash instead: Warm water and mild dish soap. Dry immediately with a soft cloth.

6. Hand-Painted or Gilded Dishes

Dishes with hand-painted designs or gold/silver trim will fade and wash off in the dishwasher. The metallic trim can also react with detergent.

Hand wash instead: Gentle soap and cool water.

7. Sharp Knives

Dishwasher detergent is corrosive to knife blades, and the jostling inside the machine dulls the edge quickly. High-quality chef's knives should never go in the dishwasher.

Hand wash instead: Wash immediately after use with warm soapy water, dry, and store properly.

8. Aluminum Cookware

Aluminum reacts with dishwasher detergent, causing it to discolor, pit, and develop a dull gray finish. This is especially true for uncoated aluminum pots and pans.

Hand wash instead: Warm water and mild soap.

9. Insulated Travel Mugs and Bottles

Unless explicitly labeled dishwasher safe, insulated mugs and bottles can have their vacuum seal damaged by dishwasher heat — destroying the insulation that keeps drinks hot or cold.

Hand wash instead: Warm soapy water and a bottle brush.

10. Cheese Graters and Fine Mesh Strainers

Food particles get trapped in the tiny holes and are nearly impossible to remove in the dishwasher. They often come out dirtier than they went in.

Hand wash instead: Scrub immediately after use with a brush under running water.

11. Anything with Paper Labels or Stickers

Labels dissolve in the dishwasher and can clog the filter and drain. Always remove labels before washing jars or containers.

12. Antique or Heirloom Dishes

Old glazes and finishes weren't designed for modern dishwasher detergents. Antique dishes can crack, fade, or lose their glaze permanently.

Hand wash instead: Gentle soap and cool water, handled with care.

Keep Your Dishwasher Running Well

Even when you load correctly, food particles and mineral deposits build up inside your dishwasher over time. Run a monthly cleaning cycle with Affresh Dishwasher Cleaner Tablets (amzn.to/42P5MKQ) to remove limescale, bacteria, and grime from the pump, tub, and hoses. And always use a quality detergent — the Finish Powerball Dishwasher Pods (amzn.to/3RE929j) are a reliable everyday choice.

Quick Reference: Never Dishwasher

• ❌ Cast iron
• ❌ Wooden items
• ❌ Non-stick pans
• ❌ Copper
• ❌ Crystal
• ❌ Hand-painted or gilded dishes
• ❌ Sharp knives
• ❌ Aluminum cookware
• ❌ Insulated mugs/bottles (unless labeled safe)
• ❌ Fine mesh strainers and graters
• ❌ Items with paper labels
• ❌ Antique or heirloom dishes