17 Things You Should NEVER Put In The Dishwasher

17 Things You Should NEVER Put In The Dishwasher

What would we do without our beloved dishwashers? They certainly make meal times convenient, but that's not to say we should put everything and anything inside them.

Although there's a lot our dishwashers can handle, the hot temperature, powerful water and detergent mean some things should never be put inside.

Our list of 17 things you should never put in the dishwasher will get any confusion all cleaned up for you.

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1. Don't put your garlic press in the dishwasher

Not EVERYTHING belongs in the dishwasher.

It's often tempting to put the things that are hardest to clean in the dishwasher, but those are often the things that absolutely shouldn't be in there.

The pressure created by a garlic press often leaves garlic pieces stuck on the inside. These pieces are wedged in so well that even the strong current of your dishwasher will struggle to remove them. It's much better to wash garlic presses by hand to ensure all garlic is removed and they are truly clean.

2. Wash your chef knives by hand

Top quality knives don't come cheap. If you've already invested in a set or are thinking about it, make sure you look after them properly.

Throw them into the dishwasher, and the abrasive detergents will wear down the sharp edges. They're also prone to move around in the wash, and these bumps won't do their sharpness any good either.

3. Don't put copper in the dishwasher

Let's face it, you didn't buy copper cookware for its heat-conducting properties alone. New copper looks stunning - let's try and keep it that way.

If you want to preserve their look for as long as possible, the last thing you should do is put them in the dishwasher. This will alter their colour, making them mottled and even giving them a rusty appearance - not exactly the interior dream you had envisioned.

Instead, try cleaning it with ketchup!

4. How to wash antique plates

Antique plates, your Granny's old cooking pot or anything that's old or has sentimental value should not be put in the dishwasher.

Many older items existed at a time when dishwashers were yet to be invented, and so they're not as hardy as those sold today.

Wash these items by hand, and admire their beauty while you're at it!

5. Are plastic containers dishwasher safe?

don't put plastic in the dishwasher
Is it 'dishwasher safe'?

It's a good question, but not one that has a straightforward answer. Much like plates, some plastic containers are deemed 'microwave and dishwasher safe'. This is usually marked on the bottom of the box.

Others, however, cannot withstand the temperatures of a dishwasher. Wash them, and the plastic may melt or the chemical composition of the plastic may be changed, making it unsafe to use in the future.

The same goes for takeaway boxes, which should never be put in the dishwasher unless stated by the restaurant.

6. Can you put wooden chopping boards & utensils in the dishwasher?

Wooden chopping boards and utensils are no different to any other wood - they should be kept as dry as possible.

To prevent wood from becoming saturated with liquid, it's best to wash them by hand. The high temperatures in your dishwasher can also cause splinters, another reason to avoid washing them in this way.

7. How to wash crystal glasses

Having to replace chipped crystal probably isn't a situation you want to find yourself in.

The easiest way to avoid it is by:

  1. Only having careful guests over for dinner
  2. Washing your crystal by hand

Whilst number one mightn't always be possible, number two certainly is. The dishwasher won't do crystal any good - high temperatures and strong detergents can cause chips and even dull their sparkle - what's crystal without sparkle!?

8. Can you wash a pet bowl in the dishwasher?

This is a tricky one! Dishwashers are supposed to get hot enough to kill the majority of germs, but the NSF found 67% of pet bowls still had Salmonella bacteria even after dishwashing. This bacteria will be washed into the water, and then swirled around, contaminating other items.

If you do want to put them in the dishwasher, we'd recommend giving them a hand wash first. 

9. Cast iron pans

washing up pots & pans
Cast iron won't fare well in the dishwasher.

The beauty of cast iron pans is that sensational seasoning that gets built up over time on the bottom of the pan. This not only makes your food taste amazing, but also prevents it from sticking.

Put these pans in the dishwasher, and that coating will be destroyed. The harsh detergent will wash it away entirely, and you'll be left with a bare cast iron surface that shows signs of rust.

10. Labels may block your dishwasher

Any labels left on packaging, jars or plates should be removed before being put in the dishwasher.

If not, you risk them becoming trapped in the filter and blocking the machine. Life without a fully-functioning dishwasher just isn't worth the risk.

11. Don't put filthy pans in the dishwasher

Sometimes, there's nothing for it but a hot soak, a bit of elbow grease and a whole lotta fairy liquid.

For filthy pans coated with grease and burnt on food, this is the best option. Although dishwashers are great, they're not miracle workers, and there's some dirt that even they'll struggle to shift.

12. The dishwasher will ruin non-stick pans

Non-stick coatings are literally a godsend. Most of us know not to use metal utensils in our pans, or abrasive sponges to scrub them clean, but did you also know they shouldn't be put in the dishwasher?

Similarly to cast iron pans, the detergent and high temperatures will wear down that non-stick coating over time, ruining your beloved set of pans.

13. Aluminium will not fare well in the dishwasher

Pots and pans in cupboard
Take good care of pots and pans.

Just like copper, aluminium items will not fare well in the dishwasher. They may become scratched, lose their shine and quickly start looking worse for wear.

Be sure to check your aluminium items are deemed 'dishwasher safe' before taking any chances.

Find out how to clean aluminium in our other article, and give the dishwasher a miss!

14. Can you put washing up liquid in the dishwasher?

Putting washing up liquid into the washing machine may seem like a reasonable idea, but I wouldn't try it if I were you.

The swishing action of your dishwasher will turn that small squirt of washing up liquid into a bubble bath that quickly seeps out onto your floor - yikes!

15. How to wash insulated mugs

Insulated mugs and dishwashers don't go well together. Depending on the quality of your mug, you could find water seeping inside the insulated later.

This will linger, providing the perfect moist environment for germs to multiply. It will also make the insulation much less effective, as this is designed to be an empty vacuum layer.

16. Cheese graters should be washed by hand

Just like those little bits of garlic in your garlic press, cheese crumbs will get stuck in and around your cheese grater - a tough job for your dishwasher to tackle.

To avoid pieces of hard cheese being left on your grater, it's best to wash by hand.

17. Don't put repaired crockery in the dishwasher

china mug in dishwasher
Items you treasure should be washed by hand.

You may have managed to piece and glue together that beloved China plate once, but it's unlikely you'll be as lucky a second time.

Don't push your luck by putting repaired items in the dishwasher. The glue will weaken and leave you with shattered shards all over again.

Next, read our article on how long dishwashers last - it might surprise you! For more dishwasher tips, check out what to do if your dishwasher isn't drying or your pods aren't dissolving

What do you hate washing by hand and always put in the dishwasher? Tell us in the comments below!

Stephanie C


Lover of all things fashion & foodie...I look to satisfy my tastes without obliterating my budget. Wannabe interior designer, I'm an avid cushion cover maker and charity shop hunter.

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  1. Author linda on October 11, 2017 at 8:18 am

    I didn't even think about the cat bowls! I rinse them then put them in the dishwasher! I must get my daughters to sign up and receive expert home tips as well ?

    1. Author Stephanie C on October 11, 2017 at 10:21 am

      Hi Linda. I would definitely advise against putting them in your dishwasher along with your own dishes - best not to risk germ contamination.

  2. Author Jo Maynard on October 11, 2017 at 8:39 am

    I am confused. No 8 says do not wash pet bowls in the dishwasher. Once i had read this artical I followed the link to '21 strange items that can be washed it the dishwasher.' No. 6 in this arrival says that you can put pet bowls in with the other plates in the dish washer. Which arrival is correct?

    1. Author Chompy on February 24, 2020 at 8:54 am

      I was also confused, as I followed the link in No 8 to the article (which is a blatant advertisement for bleach) that mentioned washing pet food mats in the washing machine as the right thing to do. A washing machine is not going to reach anywhere near the temperatures of a dishwasher and therefore also not kill pathogenic microorganisms. There seems to be a lot of contradiction on the subject.

    2. Author Joanne A on February 26, 2020 at 4:57 pm

      Hi Chompy! The article we have linked to is from another source. If you have any problems with the accuracy of that content, we suggest you leave a comment on their article instead. Sadly we can't update theirs!

  3. Author David Blackmore on October 11, 2017 at 8:41 am

    To wash your cheese grater run under a cold running water and use a sponge or soft cloth. Please take care no cut fingers please.

    1. Author Stephanie C on October 11, 2017 at 10:20 am

      Hi David. Great tip, thanks for sharing :)

  4. Author Jules S. on October 11, 2017 at 9:09 am

    You say never to put pet bowls in the dishwasher, but your link to '21 strange items that can be washed in your dishwasher' says that you should wash pet bowls that way.....though your reply to a comment about horsey items says not. Some inconsistent advice here about animal-related items. For the record, I have Great Danes and boil wash their bowls separately in the dishwasher and have been known to do the same with occasional horse items, but I do make a point of using a branded dishwasher cleaner at least once a week and clean the filters every few washes.

  5. Author christine jewels on October 11, 2017 at 9:29 am

    then what is the point? I have always put plastic containers in the dishwasher. If there are so many contraindications why use one?

    1. Author Stephanie C on October 13, 2017 at 9:50 am

      Hi Christine. Dishwashers are extremely useful for day-to-day cleaning of dishes, as well as after parties. Adhering to some of our advice means they will continue to be a positive addition to the kitchen as opposed to a negative.

  6. Author Mandy Pontet on October 11, 2017 at 10:32 am

    If you brush a little vegetable oil on both sides of a cheese grater before using, the cheese won't stick and any residue will wash of really easily!

    1. Author Mandy Pontet on October 11, 2017 at 10:33 am

      Sorry typo..should be wash off not of!

    2. Author Stephanie C on October 11, 2017 at 12:31 pm

      This is a WONDERFUL tip Mandy! Thanks for sharing :)

  7. Author Donatello46 on October 11, 2017 at 4:33 pm

    Much as I love your blog Stephanie, you've missed out two obvious items you should never put in your dishwasher - pets and children!! - Loose pet hair could clog your dishwasher, (just joking of course :-) ) Incidentally, in MY household, I AM the dishwasher!!

    1. Author Stephanie C on October 12, 2017 at 9:28 am

      Hi Donatello. Your comment made me laugh-out-loud - thanks alot! :)

  8. Author John Westwood on October 11, 2017 at 7:48 pm

    I always find your articles interesting. However I am unsure about the emphasis you put on #8 in this article. You say "Don't ever put your pet bowls in your dishwasher". This contradicts the link in #16 about "21 strange items that can be washed in the dishwasher". Item #8 Pet Bowls says "Stick them in the dishwasher with the rest of the plates". We always put our cat and dog dishes in the dishwasher as it cleans all dried food bits (if there are any left) and the final hot rinse kills any remaining germs. Any comments.

  9. Author M Badminton on October 11, 2017 at 11:15 pm

    you state in this article not to put your pet bowls in the dishwasher and i agree. However in the accompanying article 21 strange things you can put in your dishwasher it is suggested that you do and a lot worse than that! Come on make your minds up please!

  10. Author Susan on October 12, 2017 at 2:17 am

    I enjoy washing up. The hot water is great for my arthritic hands and, after a dinner party when all the guests have gone, I find it relaxing to put the leftovers away and wash up. Once I have my rubber gloves on there is no stopping me. Instead of a messy pile, organise the washing up into categories and work your way through it - glasses first, then plates and cutlery and finally serving dishes and bakeware.

    1. Author Stephanie C on October 12, 2017 at 9:27 am

      Hi Susan. I've only just got a dishwasher, and while I do find it comes in handy, I still find myself washing up quite often! There is something satisfying (and relaxing like you say) about washing up. Each to their own :)

  11. Author Heather Martin on October 16, 2017 at 12:54 pm

    Every time I put on a cycle then in goes my washing up brush , scrubby green sponge and dishcloth .

    1. Author Stephanie C on October 18, 2017 at 9:37 am

      Hi Heather. That's a good idea! We'll have to try it. Thanks for sharing :)

  12. Author Clare on June 17, 2019 at 9:16 am

    thank you for these tips I am disabled and I struggle doing the washing up now so we got a dishwasher and I didn't know what you can and cant put in the dishwasher so thank you

    1. Author Joanne A on June 17, 2019 at 10:11 am

      You're very welcome, Clare! I'm glad that these tips will be able to simplify life for you.

  13. Author Steven L on October 11, 2019 at 9:06 am

    Very good list. However even the plastic containers that say dishwasher safe often distort and you can find the lids do not fit properly after. I never put plastic into a dishwasher. If you do, then don't use the 60 wash, use eco which is around 50 degrees.

    1. Author Joanne A on October 11, 2019 at 10:27 am

      Thanks for sharing, Steven!

  14. Author Tina B on February 18, 2020 at 2:49 pm

    I had a new kitchen 18 months ago I have the dishwasher once I find it quicker cleaner and easier to wash by hand

    1. Author Joanne A on February 18, 2020 at 4:31 pm

      I agree! Though it does depend on how many people live in your home. If you're constantly washing up plates for a large family, a dishwasher can be a god send.

  15. Author Withheld on June 12, 2021 at 7:52 pm

    My husband works for a well known white goods company. He repairs said item. You would be amazed at what people put through their dishwashers and other appliances! He is always saying that it is a dishwasher not a garbage disposal unit! Lots of people put things in their dishwashers that still have food on them and the filter gets blocked up. Please rinse things off before placing them in your dishwasher.

    1. Author Joanne A on July 5, 2021 at 5:49 pm

      Great tip - as simple as it might sound!

  16. Author Barbara Pritchard on November 29, 2021 at 2:15 pm

    I just don’t like dishwashers. My other half loves them so I’m really happy when he goes away and I can hand wash everything.

    1. Author Joanne A on July 28, 2022 at 10:33 am

      Hand washing can be rather relaxing!


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