15 Things You Probably Shouldn’t Put in the Dishwasher

updated Feb 2, 2021
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(Image credit: Przemyslaw Ceynowa)

What makes something dishwasher safe — or better yet, not dishwasher safe? A few things, actually. First, you have to consider the material. For example, wood can crack or warp from the high, high heat during the cycle. Too-thin plastic can melt. Knife blades can rust. (If it’s a carbon steel knife with a wooden handle, the the blade can rust and the handle can crack!) You also have to consider how fragile an item is. Could it break if it’s jostled around or if something else is jostled around and falls on it? (If so, it’s best to leave it out.) And you have to think about the finish. For example, is there a nonstick coating that could break down over time?

Although there is a litany of strange things that are OK to put in the dishwasher, there are also plenty of things that shouldn’t go in there.

Here are a few kitchen items that you should consider hand-washing instead of putting in the dishwasher.

Credit: Joe Lingeman

15 Things That Really Shouldn’t Go in the Dishwasher

  1. Cast Iron: Cast iron requires a little more attention and care than your other pots and pans and shouldn’t be put in the dishwasher. See our tutorial for how to properly clean cast iron.
  2. Good Knives: This is what happens to your knives when they’re put in the dishwasher. (Hint: They dull quickly! And could rust!) Consider it a cautionary tale.
  3. Crystal: This is an obvious one. Dishwasher detergent and heat can potentially chip or crack fine crystal. Or something could fall on your favorite crystal candy dish and break it. Don’t risk ruining your very expensive and precious items, and just hand-wash ’em instead.
  4. Wooden Utensils: Some wooden or composite items can go in the dishwasher, but it’s best to check with the manufacturer first (if possible). You risk having the wood warp or lose its finish.
  5. Nonstick Pans: Again, it’s best to check with the manufacturer to see if your nonstick can be put in the dishwasher. But in case you don’t know the brand or want to be super careful, nonstick is best to hand-wash. You risk the pan losing its nonstick qualities.
  6. Copper Pans: You risk changing the color of these gorgeous pans by putting them in the dishwasher.
  7. Soft and Hard Plastic: Some harder plastics can be put in the dishwasher if the manufacturer says it’s OK; just make sure to put them on the top rack.
  8. Baking Sheets: Baking sheets can easily discolor or warp after just a few cycles in the dishwasher.
  9. Disposable Aluminum: You risk getting black residue or marks all over the aluminum item and the other things in the dishwasher.
  10. Gold-Plated Dishware: The dishwasher can potentially eat away at the gold. It’s better to avoid ruining your plates or silverware and simply wash these items by hand.
  11. Insulated Mugs and Water Bottles: Put these in the dishwasher and the space between the outer and inner layer could end up filled with water. Not cool.
  12. Anything with Adhesives: Labels with glue can come off and clog your dishwasher. It’s best to either get rid of the labels before putting the item in the dishwasher (like with glass bottles), or simply wash by hand.
  13. Enamel: Those campy plates and cups are super trendy these days. Lots of companies say their enamel is dishwasher safe, but try to keep the cycles to a limited number. Over time, dishwasher detergent can reduce the luster and shine of your enamel pieces. And we’ve seen older pieces get these weird bubbles and start to flake. Wash by hand if you can.
  14. Milk Glass: Milk glass can easily be chipped in the dishwasher.
  15. Hand-painted pottery: If you paid a pretty penny for something that’s hand-painted, you might want to hand wash it. Yes, even if the maker says it’s dishwasher safe.

Got any others to add to this list? Or maybe you DO put some of these things in the dishwasher? Discuss in the comments below!