Home Decor

15 Things You Should Never, Ever Put in the Dishwasher

Read this before your next cycle.

September 11, 2019
Photo by Rocky Luten

My motto when shopping for home goods is, “If it doesn’t go in the dishwasher (or washing machine), it doesn’t go in my house!” Washing dishes is one of my least favorite chores, so I do my absolute best to keep hand wash-only items out of my cabinets.

But despite my efforts, there are still a number of kitchen essentials I end up hand-washing, typically because I didn’t read the fine print when I bought them. (Seriously, who knew box graters shouldn’t go in the dishwasher?)

If you’re guilty of skipping the fine print, too, you might not realize that a few core kitchen items are actually only supposed to be hand-washed. To keep your tableware, cookware, and other kitchen accessories in top shape, make sure to keep these 15 things out of the dishwasher:

1. Cast Iron

Hopefully this doesn’t come as a shock, but your cast iron pans should never go in the dishwasher. In fact, you shouldn’t even use soap on them if you can help it. Soaps and abrasive sponges can damage the finish and seasoning of your precious pan, so stick to using coarse salt to scrub it down.

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Top Comment:
“I wash my sterling silver in the dishwasher (Miele) because we use it for every meal. When we received it from my mother-in-law's estate, silver cleaner paste was in the floral/fruit crevices at the base of each piece. The silver was only used it at Thanksgiving, etc. It won't wear out in my time, so we use it everyday. It has never looked better and gives me great pleasure to cherish a timeless gift.”
— Susan W.

If you do accidentally wash your cast iron pan with soap (my roommates have done this to me before), don’t stress. It’s easy enough to reseason cast iron—you just need to oil it up, and bake it in the oven.

2. Nonstick Pots & Pans

The reason it's said you should never use metal utensils on nonstick pans is that they can damage the finish, ruining the effectiveness of the nonstick surface. The same thing can happen if your pots and pans get banged around in the dishwasher—the surface can get scratched, shortening its lifespan.

3. Crystal

Crystal glasses are delicate, and the high heat and/or water jets in your dishwasher can cause chips or cracks. Even if they do make it through the cycle, your glasses may develop a cloudy residue over time—so stick to hand-washing crystal and fine wine glasses.

4. Wooden Cutting Boards & Utensils

Wood and dishwashers just don’t mix. The heat of the dishwasher can cause wood to warp, and the drying cycle can make it crack. So please, keep your wooden cutting boards and utensils out of the dishwasher.

5. Insulated Travel Mugs

Most travel mugs have a special vacuum seal between the inner and outer shells, and this seal can be ruined if you put the cup in the dishwasher. Not only will this compromise the effectiveness of your best travel mug, but you may also get water in the walls that sloshes around as you drink.

6. Copper Pans

Copper is prone to tarnishing, and the harsh conditions of the dishwasher can ultimately ruin the shine of your beautiful copper pots and pans. Given that they’re typically quite pricey, I think it’s worth hand-washing them to protect your investment.

7. Your Best Knives

Of course you can put your butter knives in the dishwasher, but you might want to think twice about putting good kitchen and prep knives through the cycle. Why? The harsh conditions of the appliance can dull the edges of blades, forcing you to sharpen them more frequently. It can also cause carbon steel and other materials to rust.

8. Graters

There are two reasons to wash graters by hand. First, similar to with knives, the dishwasher can dull graters' blades. And second, chances are, a dishwasher won’t be able to get all the particles out of their little holes, so you’re better off doing it by hand anyway.

9. Aluminum Pans

Both aluminum cookware and disposable aluminum trays will become discolored when put into the dishwasher, if not sealed in some way. The metal can react with water and air in a process called oxidation, and becomes covered in a dark film that then rubs off on other items.

10. Pressure Cooker Lids

While technically the top of your Instant Pot is dishwasher-safe, it’s not the best cleaning option, as there are a number of important components in the lid of a pressure cooker. For instance, there are values that can get clogged with food particles, as well as seals that may be damaged by the dishwashing chemicals—both of which will shorten the lifespan of your appliance.

11. Milk Glass

The pure white hue of milk glass makes it a treasured collection piece for many, and it’s important to learn how to care for this material properly if you want it to last. Milk glass can take on a yellow tint if put in the dishwasher too many times, so you’ll want to wash it carefully with a gentle cloth and soapy water.

12. Thin Plastic Containers

Unless you know for a fact that a plastic container is dishwasher-safe, I’d recommend scrubbing it down the old-fashioned way. Thin plastic will sometimes melt or warp in the dishwasher, rendering the container useless—a lesson I’ve learned the hard way.

13. Pop-Top Storage Containers

Airtight storage containers are a must-have in any pantry, but when it comes time to clean them, the dishwasher is a gamble. Many say they’re dishwasher-safe, but the gaskets can warp and seals can break down if you wash them frequently.

14. Family Heirlooms

In general, it’s best to leave anything precious that's missing cleaning instructions out of the dishwasher. This applies to fine china, your grandmother’s favorite mixing bowl, or whatever else you hold near and dear. Don’t risk it getting dinged in the dishwasher!

15. Items with Labels or Adhesives

If you’ve ever put an empty pasta sauce jar through the dishwasher (guilty), you know that the label comes out a torn, soggy mess. Not only will the hot water ruin the label, but the pieces that flake off can clog your dishwasher’s filter, as well.

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Freelance writer, product tester & baking enthusiast.


baileychic8 July 2, 2021
Car parts. My ex is a mechanic.
Gina G. March 1, 2021
Pls do not put any item with a rubber gasket in, something like the lid for your Sous Chef or glass storage jar or blender cover or blade seal. They warp or melt and never seal properly. And you won’t believe what a lengthy and expensive hassle it can be to replace that Sous Chef lid!
BoulderGalinTokyo February 28, 2021
After years of helping exchange students and other foreign language learners I really have to teach dishWASHER soap and Dish washing liquid as soon as they move in. One lady filled the dishwasher soap holder and she had bubbles throughout her entire living room!
Alex S. February 28, 2021
When I shared an apartment with my college-aged brother, and we ran out of dishwasher soap, we sometimes tried to use a tiny amount of powdered laundry soap. It could cause the same disastrous results as the lady and her living room. Those excess suds really cleaned the kitchen floor though!
Nkolew December 1, 2020
Sooooo, then basically nothing in your kitchen can go in the dishwasher? The designers should probably change the designs of dishwashers then.
Melissa August 21, 2020
Silver As in actual "silver" ware
Caroline L. March 2, 2021
Silver is fine to go in the dishwasher if you follow the rules - no lemon detergent, no heated try, don't let it touch anything stainless steel. Some people don't put the knives in because of the glue holding the blade and handle together, but it takes a very very long time for that to be an issue.

If it's the difference between using it and leaving it in storage, I absolutely encourage people to wash sterling in the dishwasher. Estate silver expert Beverly Bremer gives it the OK, which is good enough for me. It can get a little cloudy over time, but no faster than it would take to tarnish - so I'm happy to polish it off when that time comes.
Marla K. December 29, 2019
I put both my box grater and microplane in the dishwasher, no problem with either.

I also put my wooden utensils in the dishwasher on the top rack. They're cheap enough, so that when one warps and breaks, I can easily replace it.

I also put those 'disposable' storage containers and Tupperware in the dishwasher, again top rack only.

Why have the damn thing, if you're not going to use it?
arcane54 December 25, 2019
The cloisonné brasswork your grandfather picked up in the Middle East when he was a merchant seaman in the 1940s. Just. Don’t.
jpriddy October 20, 2019
Reading through comments, I would add simple advice: Do not allow guests to "help" by loading the dishwasher. They will put things in that you do not washed as well as loading the dishwasher in ways you do not want it loaded. I recall a serious argument when a friend insisted on putting my wooden spoons in the dishwasher and I took them back out. Now we just say no-thank-you to people who offer to help.
Liz C. December 29, 2019
Your comment reminded me of a story. My grandmother got a dishwasher before the rest of the family. It wasn't until I moved out that anyone else had one. So the next time we were all cleaning up after dinner I loaded the dishwasher. My mother and aunts all stood back and held their breath. I didn't know but apparently, my grandmother never let anyone load the dishwasher. I passed :)
ThePickledFig March 1, 2021
Everyone definitely has their way to "best stack a dishwasher". The University of Birmingham even codified these bitter arguments in a paper too! They found 42% of people reload their dishwasher because they believe it is done incorrectly. IMO, it is easier to designate who in the family loads it and leave it at that. When I go to my parents house, my mom loads it; when she is at my place she knows I load it. We are both horrified by how we each load our machines (for example, I am not in the camp of overstacking a dishwasher - all items must easily be hit by water; my mom, however, fills every space available before running!). Agreed, it's also ok at to tell guests no to helping or, if quiet spoken, just reload after they leave - no rule the dishwasher must be run after loading =) Honestly when it comes down to it, everyone has items they are ok or not okay going into the dishwasher. For example, the cheap wooden spoons I get at HomeGoods go straight into the dishwasher because they are easy to replace. The pricey and unique wood serving piece that I want to last for years is hand washed.
Roberta October 18, 2019
Don't wash stainless steel and sterling silver in the same load. Better yet, don't put sterling silver in the dishwasher.
pat October 18, 2019
salad spinners-
Barbara R. October 29, 2019
Why not? Just curious what might happen to the salad spinner. It seems like it might be okay?
pat October 29, 2019
mine says do not wash in Dishwasher.. but additionally i try to avoid putting anything plastic in the dishwasher: i saw this: The chemicals found in certain plastics can be harmful to kids when heated. ... Because heat can cause plastics to leak BPA into our food, the AAP suggests not microwaving food or drink (including infant formula and breast milk) in plastic and to avoid putting plastics in the dishwasher altogether
Liz C. December 29, 2019
Yes, I'd really like to know how much of the toxins found in our water system came from washing plastics in dishwashers. BPA, formaldehyde, etc.
liz S. October 18, 2019
Other no-no's include anything with gold rims: the detail on my glass salad bowl almost disappeared after a friend dw'd it without asking me.
leslie F. October 17, 2019
Anything that has candle wax on it!—the little plates, the glassware candlesticks, any and everything that our lovely wax candles dripped upon LOVES the high heat of dishwashers and spreads a lovely wax coating on every, single, wingle thing in your dishwasher. And once gone through dryer mode, it’s all nearly impossible to clean off.
So do not put candle wax in the dishwasher. (And while we’re on it, not the washer either. Creates a similar nightmare.)
Fred K. October 17, 2019
I read through all the comments looking for this additional reason to never put aluminum in the dishwasher: little bits of it will migrate to china and remain there, waiting to be laboriously scrubbed off!!!
kat October 17, 2019
How about all the things I put in the dishwasher?? I took a small cat carrier apart and ran it through my dw. Perfect! Also I have some sandals that are made of some extruded plastic/or other strange lightweight material--they are great to run through dw after a trip to Mexico.
AlwaysLookin October 17, 2019
You should FLAG this, 'not for experienced cooks' ... most aren't this silly to think they should wash these items in a Dishwasher.
Janet C. October 18, 2019
You would be surprised what experienced cooks don't know. I have a friend that would think nothing of doing most of the above and she's been cooking for decades. Yes, she lives under a rock, but then I have another friend who argued with me about how many tsps make up a T. She's also been cooking for years. I bought her a conversion chart.
t October 17, 2019
Not sure on the advice on not washing Cast Iron pans w soap. My Grandmother is 96 years old and the pans she has were her grandmother's and we have been washing them with Soap for years...still the best cooking pans.
Must be the " new and improved " Cast Iron pans...
No matter, they last lifetimes !
Irene December 29, 2019
Have always washed my Cast Iron with soap. Just need to put on the stove top on high heat to dry, rub with oil and you're good to go!
Valli K. February 28, 2022
Me too!
Ray October 17, 2019
Most melamine is labeled "not dishwasher safe" which makes it a non-starter for me. Sometimes I put my heavily soiled Bourgeat copper cookware in the dishwasher. The handles come out rusty, but I scrub the handles and exteriors of the pots and pans with Barkeepers Friend and wax the iron handles - poof, good as new. Never had any issue with graters, and some of them are decades old.
MaryBeth C. October 17, 2019
Fine China especially older patterns. The holy edges can be a matched off, and the detergent can cause craze marks. If you love it, hand wash it.
cynthia October 17, 2019
I have always heard about knives getting dull edges from being in the dishwasher. What I don't understand is how that happens. What exactly is dulling the edges?
Janet C. October 18, 2019
Means the edges are no longer sharp and before you can efficiently use them to cut, you will need to sharpen them.
W J. November 10, 2019
While some tell you that it is the jostling of the knife edges that dulls knife edges or some say that it is the high "abrasiveness" of dishwasher detergents, I am of another opinion.

I think that it is the caustic nature (high pH) of the detergents and chemicals used in dishwasher soaps that is the true and unrecognized culprit. What most do not realize is that your dishwasher is actually a hot chemical wash cabinet. It is the detergents and the mix of caustic chemicals that actually do the cleaning along with very hot water. The spray arms and mechanisms of a dishwasher just distribute the chemical cleaning solution.

A very sharp knife has a microscopically fine foil edge. It doesn't take much in the way of corrosion or pitting to destroy the integrity of that edge. A less sharp knife, well, perhaps not so much as it wasn't very sharp to begin with.

Many knifes, today, are made of stamped stainless steel and very high end knifes are layered carbon steel with a stainless steel skin or top layer. The high carbon content makes them very hard and able to hold a sharp edge for quite a while. But in a hot, corrosive bath with plenty of oxygen present, you can bet that you are going to get some electrolytic microscopic pitting and corrosion, especially on the thin, thin edges.

One should never even soak a high end knife such as a high quality chef's knife, paring knife, bread knife, etc., but rather rinse and dry it immediately after use.

BTW, the same is true for razor blades. Corrosion kills the edge faster than does shaving, so it pays to dry the blades of a razor immediately after use.
viviancooks December 29, 2019
It has always been my understanding that you should never put a full tang knife in the dishwasher....ruins the handle. (And the most expensive knives are usually full tang.) I have no problem putting in knives that are not full tang. And they dont seem to lose their edge.
timhood February 28, 2021
I have a set of Wusthof knives I purchased over 30 years ago. They have composite handles. I've been washing them in the dishwasher their entire life. I think this old wives take originated when knives had wooden handles, which was when you wouldn't want to wash them because the handles could eventually separate from the tang. If dishwashers weren't safe for knives, neither would they be safe for pots and pans, flatware or anything else metal. I wish I could upload pics to show my knives are just fine.
Susan P. October 17, 2019
Don't put the wire whisk attachment of your Kitchenaid mixer in the dishwasher. I thought they were being extra cautious when they said not to, and how the heck are you supposed to get all the oily residue off after you make mayonnaise? Anyway, the wires of this attachment are made of stainless steel, but the body is made of aluminum so galvanic corrosion forms a black powdery residue on the body that makes a huge mess on you hands and everything else it touches. Eventually I think the wires would come out of the body due to this corrosion. How much more would it cost to make both parts of this attachment out of stainless steel so it could be washed in the dishwasher? I don't know, but I would be happy to pay extra so I don't have to clean this by hand.
Caroline L. March 2, 2021
I totally agree! I actually went to the KitchenAid website and ordered an all-stainless whisk after making this mistake twice (well, once was my fault and the other time someone put my replacement in the dishwasher for me). I would have paid more up front for the mixer to not have to deal with that!
paseo September 26, 2021
All that you say is true, what a pain in the tuchas that was to clean! Only once, I might add. Another item not to put in is anodized aluminum pots and pans.