29 Things to Never Put in Your Dishwasher

Even though the first dishwasher was developed in 1850, and dishwashers have (thankfully) gone through numerous improvements since then, some items are still best washed by hand.

And by that, we don’t mean the really unconventional stuff that some folks like to put in their dishwashers. Apparently, giving a hat or a keyboard a carwash-style experience in your home has become a thing.

We figure you already know that’s a bad idea.

We wanted to ensure that you know how to treat common items in your kitchen with the right care in order to save the money and hassle of having to replace them.

So we compiled a list of things that you might think are safe to place in your dishwasher, but actually aren’t.

Let’s start with the first item on the list!

1. Garlic press

A garlic press comes with so many benefits: no more time wasted on chopping, no more sticky-smelly fingers, and no cutting board mess. But there’s a downside. If you simply place it in a dishwasher, chances are high it’ll come out almost as dirty as it was before. The bits and pieces of garlic that get stuck in the crevices are simply too much for your dishwasher to take. A spotless garlic press requires hand washing to get the job done.

2. Pet dishes

Fido is fun and loyal, makes you exercise every day, and has become your family’s best friend. His mouth also is home to lots of bacteria that are different from yours. Some of these bacteria can be good for challenging your immune system—but some, like capnocytophaga canimorsus, can get you sick if your blood happens to already have elevated levels of iron. If you place your pet’s dishes in your dishwasher, chances are their bacteria will spread over onto your dishes. As a result, you might be perfectly fine… or you might end up with a fever, diarrhea, abdominal pain, headaches, and skin rashes.

3. Dishes with big pieces of food on them

The good news is that you don’t have to pre-rinse your dishes before placing them inside your dishwasher. Modern dishwashers have been equipped with sensors that can recognize food residue on your dishes and adjust the length of the dishwashing cycle in response. But you still need to scrape off large pieces of food to prevent them from ending up on the other (cleaner) dishes.

4. Wood

Placing wooden items into your dishwasher will ruin the finish and make them crack as they dry. Food can easily find its way into these cracks, which creates a perfect environment for germs to grow, which will eventually turn parts of your wooden item black. To prevent this, it’s best to hand wash wooden items.

5. Your cheese grater

As soon as you’re done using your cheese grater, the sticky cheese residue on it begins to harden and becomes even stickier. This is an impossible mess for your dishwasher to clean up. The better way of taking care of this is to immediately wipe the grater with a kitchen cloth to remove most of the leftover cheese, followed by hand washing it with dish soap applied with a sponge.

6. Your sieves

The small holes in sieves make it nearly impossible for dishwashers to remove all of the food residue stuck in them. The best way to wash a sieve is to either soak it in water right after you’re done using it. Then hand wash with a dish brush that can easily get into the little holes to prevent dried food from getting stuck.

If you’re looking for an eco-friendly dish brush that was built to last, made out of natural materials, then check out this brush. Instead of cheap plastic it was made from beechwood and natural fibers. It’s ideal for heavy-duty cleaning especially suitable for your dirty sieves, pots and pans.

7. Sharp knives

Dishwashers will dull your sharp knives. The easiest way to take good care of your knives is to rinse them right after you’re done using them to remove food residue and prevent it from hardening on the knife. If dried food ends up getting stuck on your knives anyway, soak them for a couple of minutes (instead of scrubbing vigorously with a sponge). Once the dried food comes off easily, carefully wash the knives with a sponge and dish soap.

8. Hollow-handled utensils

Some kitchen utensils are made from two or more pieces glued together. For these utensils, the high temperatures inside dishwashers can loosen the adhesive, eventually causing the handle to come off. To prevent the handles from falling off, it’s best to wash these utensils by hand.

9. Baking mats

Reusable baking mats break down over time if you place them in your dishwasher. The best way to wash them is to soak them in hot water with some dish soap, and then hand wash them using a sponge and more dish soap.

10. Non-stick pots and pans

Putting nonstick pans into the dishwasher can severely damage the coating. This is dangerous because the non-stick coating on these pans contains toxic chemical like polytetrafluoroethylene and perfluorooctanoic acid. If the coating becomes damaged, these toxins escape in to the air or leak in to your food, where they can harm your lungs and other organs. Better “stick” to hand washing your nonstick pans instead. Be sure to avoid using any rough scrubbers on them that could scratch the coating.

11. Cast iron

If you put a cast iron pan into the dishwasher, the harsh detergents will ruin the “seasoned” nonstick surface that is so hard to build back up, and risk rusting t,he pan. Instead, you should wash the pan with plain water. If the pan is very well-seasoned, you may use a small bit of mild natural dish soap to clean it. Don’t soak the pan, however, because this might provoke rust. Instead, loosen stubborn food-remains by scrubbing the pan with table salt and water, or use a special brush that is specially designed for cast iron pans.

Finally, dry the pan with a kitchen towel and rub it with olive oil.

12. Dishware with metallic decoration

If you own dishware with metallic decoration (which is especially common on trims), you should always wash these items by hand, and never in the dishwasher. Otherwise, the dishwasher will slowly wash away the metallic decoration.

13. Your sink stopper

Please don’t put your sink’s drain-stopper in the dishwasher. The stopper is in close contact with the sink’s drain pipes, which are a paradise for all manner of smelly germs that can easily spread inside the dishwasher to all of your dishes. A better way to clean your drain stopper is to soak it in vinegar. The acidity of white vinegar will nix the smelly germs without spreading them to your dishes. Alternatively, there is a special kind of dish soap that you can hand-wash the stopper with that will discourage the new growth of smelly friends in the near future.

14. Delicate items

Delicate, easily-breakable items should not go into the dishwasher. Any antiques and hand-blown glass items should be washed by hand, as should most wine glasses.

15. Plates you've glued back together

The high temperature inside of a dishwasher weakens adhesives - especially when combined with the harsh chemicals in dishwashing detergents. It’s best to wash glued-together items by hand.

16. Hand-painted ceramics

The same chemicals and heat inside a dishwasher that are bad news for adhesives can also easily ruin the colors on any hand-painted item. Hand wash them instead.

17. Crystalware

Crystal should look shiny and new – not dull and clouded. Refrain from washing it in your dishwasher to keep your crystal doing what crystal does best: sparkle and shine.

18. Milk glass

Milk glass is white (non-Corningware) decorative glass. You might be able to get away with washing a milk-glass item in the dishwasher a couple of times. But put it in the dishwasher one time too many, and suddenly it might turn yellowish. If you’d rather not gamble with milk glass, wash it by hand.

19. Gold-colored flatware

Anything gold colored will lose its shininess after a while if washed in the dishwasher. Better hand wash such items.

20. Brass or bronze items

Metals like these will lose their good looks if washed in the dishwasher. It’s recommended to hand wash them instead.

21. Aluminum cookware

Aluminum is sensitive to high-temperature water and harsh detergents. Your items will start looking dull after washing them a few times in the dishwasher.

22. Plastic items

Make sure the manufacturer of a plastic item clearly states that the item is dishwasher-safe. Always keep plastic items away from the dishwasher’s heating element, and place them on the upper rack to prevent them from melting.

23. Thin plastic containers

Reusing thin plastic containers such as deli containers is good for reducing trash. However, the high temperatures inside your dishwasher can warp them. Also, the water-jet inside the dishwasher can easily flip over lightweight plastic containers during the wash-cycle, leaving them inadequately cleaned. To prevent them from melting it’s best to hand wash such items.

24. Pressure cooker lids

Pressure-cooker lids don’t belong in your dishwasher. A pressure cooker’s sealing rings are crucial to it functioning properly, and the dishwasher’s high heat can easily warp them. Additionally, detergent and food particles can easily end up getting stuck inside the lid and ruin your next meal. Whether you have a stove-based pressure cooker or an electric one, the lid is best washed by hand.

25. Insulated mugs and thermoses

The weakest part of an insulated mug is its vacuum seal. To prevent it from melting or breaking, it’s best to hand wash at least the seal.

26. Acrylic dishware

Wash these items by hand because the harsh detergents and high temperatures in dishwashers will lead to cracks and damage them.

27. Measuring cups with printing

If you want to protect the printed measurement units on the side of your measuring cups, it is best to wash them by hand. Otherwise, dishwashers will remove them over time.

28. Anything with paper labels

Hot water and harsh detergents will most likely weaken the adhesive on any sticker, which might initially sound good (if you want the label off). However, on the way out they’ll clog up your dishwasher’s drain. We recommend washing jars by hand. However, if you want to put them in the dishwasher, be sure to remove the labels first.

29. Dish-washing liquid

In your a dishwasher, you should never (ever) use dish liquid that is made for hand-washing dishes in the sink. Dish soap designed for doing dishes by hand creates bubbles. Dish soap for dishwashers, on the other hand, is made bubble-free. If you use a bubbling dish soap in your dishwasher, the bubbles will likely cause your dishwasher to overflow, creating a huge mess in your kitchen. Always go for dishwasher detergent – not dish soap – if you’re doing your dishes in the dishwasher.

Over to you

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(When you make a purchase from links in this post we might receive a small commission at no additional cost to you.)