15 items you should never EVER put in the dishwasher

Your wooden spoons should never see the inside of the machine...

(Image credit: Getty Images/iStockphoto)

Dishwashers are arguably the best invention since sliced bread, but did you know that there are so many frequently used household items that you should never put in there?

It's so easy to pop your wooden chopping board or favourite pan into the machine and let it do all of the work on your behalf, but in some cases your trusty dishwasher is most likely doing more harm than good.

So, if you want to extend the life of your favourite chef knives and avoid your Tupperware boxes losing their shape, read on...

1. Sharp knives

Unless you have a drawer for cutlery in your dishwasher - fancy! - the internal plastic of the dishwasher will be nicked by the knives. Dishwasher detergent can also dull the blades, and the rattling, hot water and dry heat that dishwashers are famous for will loosen a wooden handle. Save your dishwasher and wash knives by hand - in hot soapy water if you've been cutting meat or fish, otherwise just with a damp cloth.

2. Iron pans

If you've got heavy duty cast-iron pans and you want them to last over the years, then skip the dishwasher and rinse them in warm water after use. Don't add any soap, as it wears away the patina (coating) - you can always rub the base with salt every few washes to scrub away any invisible leftover food.

3. Nonstick pans

The nonstick coating on this type of pan won't last with repeated dishwasher trips, so hand-wash with dish soap and a sponge - no Brillo pads!

4. Wooden utensils

Hot water and drying heat is too strong for the wood, and can cause utensils to warp and lose their shape. Rinse them in warm water, with no soap, and rub them with salt every so often to give them a good scrub and remove any lingering bits of food.

5. Plastic

Some softer plastics won't hold up in the intense dishwasher environment, but check the manufacturer's instructions. If they're dishwasher approved, then place them in the top rack where it's less hot.

6. Wooden cutting boards

Like spoons and spatulas made from the same material, wooden boards will warp with the intense heat of the dishwasher. If you've been chopping smelly foods like garlic, or meat or seafood, mix 25ml of bleach in half a litre of water and wash. Alternatively, you can scrub them clean with baking soda.

7. Gold-trimmed or hand-painted china

Hot water and dishwasher detergent can strip painted or gold details away, so gently hand wash instead!

8. Dishes with burnt-on food

If you've accidentally scorched your dinner, the residue will end up clogging your dishwasher, which is an absolute pain to sort out! You'll need to put some handiwork in for this one - soak oven dishes or pans in soapy water for an hour, and the food should scrub right off.

9. Garlic press

Bits of garlic can get stuck in the nooks and crannies, and the heat of the dryer setting in the dishwasher can bake them onto the press. Gross! Wash yours by hand in warm water and dish soap as soon as possible after use instead.

10. Crystal

High water temperatures can crack or dull crystal, but some crystal products will be dishwasher safe - just anchor them down properly so they don't knock around inside! If your crystal isn't dishwasher-safe, then carefully hand wash in your sink using dish soap, warm water and a splash of white vinegar.

11. Travel mugs

Check the bottom to see if it's dishwasher safe, otherwise the insulation can be destroyed by water getting inside the outer and inner layer. Hand wash in the sink!

12. Bottles with paper labels

Both the paper and the glue can clog up the dishwasher filter - not great news long-term. You can get rid of the glue left behind by rubbing vegetable oil on the sticky place, leaving it covered with a tea towel for a couple of hours, and then scraping it off using a plastic utensil.

13. Anything aluminium

Aluminium will become discoloured over time, and disposable containers can actually leave black residue all over the inside of the dishwasher. Hand wash your baking trays, or for big gatherings, recycle disposable aluminium.

14. Copper

Your pretty copper pans will dull very quickly if you put them in the dishwasher. To wash copper, put some salt over the dirty areas, pour some white wine vinegar over the top, top with some more salt, and watch the magic happen! Scrub it with a sponge et voila.

15. Cheese grater

Like the garlic press, there are a lot of crevices on a grater for food to get stuck into. Wash yours by hand, but watch your fingers...


Trusted, informative, and empathetic – GoodToKnow is the ultimate online destination for mums. Established in 2007, our 15-year-strong archive of content includes more than 18,000 articles, 1,500 how-to videos, and 7,000 recipes.