21 Things You Shouldn’t Put In the Dishwasher


In an ideal world, everything we use in the kitchen could simply be loaded into the dishwasher at the end of the day and come out sparkling clean and made anew. Unfortunately, a fair amount of what we use in our day-to-day lives in the kitchen actually isn’t safe to put in the dishwasher for a myriad of reasons.

While your dishwasher can handle a lot of the workload, there are a lot of things better washed by hand. Some can’t withstand the high temperatures, others are affected by the detergent itself.

Here are 21 things you should not put in the dishwasher:

  • Cast iron
  • Nonstick cookware
  • Copper cookware & dishes
  • Ceramic Cookware
  • Pressure cooker lids
  • Sharp knives
  • Wooden utensils
  • Insulated/travel containers
  • Sieves
  • Graters & blades
  • Gold flatware
  • Crystal
  • Milk glass
  • Metallic trimmed china
  • Hand painted items
  • Customized mugs
  • Vintage items
  • Repaired dishes
  • Certain plastics
  • Acrylic dishes
  • Paper & printed labels

While a lot of everyday kitchen items are designed to go into the dishwasher, these items are better off with an old-fashioned hand washing. Next time you are loading up your machine, take a minute to decide if it is really worth the risk of ruining your kitchenware.

Here are some explanations as to why keeping these items out of the dishwasher is best:

Cast Iron

Prone to rust and easily stripped of its seasoning by harsh dishwasher detergents, cast iron can quickly be ruined by one cycle through the dishwasher.

While it can be revitalized, you will lose all the built-up seasoning on the pan. If you do accidentally wash your cast iron, check out this article on how to properly restore it.

Nonstick Cookware

Because of the coating, nonstick pots and pans should not be cleaned via the dishwasher. The high temperature and chemicals in the detergent will quickly ruin the nonstick element of the coating, defeating the entire purpose of the cookware.

Another reason why nonstick items should be washed by hand is to keep them from banging up against each other and scratching the coating. High-pressure water jets tend to cause dishes to bump up against one another.

Some manufacturers claim their non-stick products to be safe in the dishwasher, however, you are most likely putting your cookware at risk if you decide to take the gamble.

Copper Cookware & Dishes

Copper cookware is beautiful, expensive, and has no place in your dishwasher. It will soon become dull and worn-looking if it isn’t cleaned properly and by hand. This goes for those Moscow Mule copper mugs you have as well.

If your copper does need a refresh, try applying a layer of ketchup. After rubbing the ketchup on the surface, rinse and dry to restore gleam. Commercial polishers are also available.

Ceramic Cookware

Ceramic cookware is actually made out of metal that has been coated with a layer of ceramic. It is great for its non-stick properties, but any movement in the dishwasher could scratch the surface.

Because of chemicals used in detergents, the coating can also be damaged. Many ceramic cookware pieces are marked “dishwasher safe”, but if you want longevity out of your item be sure and hand wash it.

Pressure Cooker Lids

While many pressure cookers and Instant Pots say their lids are dishwasher safe, food particles and detergent debris can get stuck in the valve and seals. If needed, rubber sealing rings can be removed and run through the cycle on their own.

Sharp Knives

Both for safety and to keep knife edges and handles at their best, hand wash knives and dry immediately. Be sure to pay attention to any screws or pins in the handle as well when drying as these areas are prone to rust.

While it may seem like knives should be fine in the dishwasher, minute nicks in the blade and damage to your dishwasher’s racks can occur and cause problems in the future.

What is safe to add to the cutlery basket of your dishwasher is knives that don’t have an edge to lose- aka butter knives. Certain cheese knives will fare fine as well.

Wooden Utensils

Wooden cutting boards, bowls, and utensils don’t do well in the dishwasher. The hot water causes the wood to swell and warp. It also strips natural oils from the wood leaving them dry and prone to cracking.

Even when hand washing, don’t let wood items spend much time in the water. Use a gentle soap and towel dry before placing them to air dry all the way.

If your wood cutting boards have an unpleasant odor, rub with half a lemon or white vinegar and let air dry. This will help eliminate the odor.

Insulated/Travel Containers

Whether it is your trusty travel mug or those double-walled tumblers you pull out for summer picnics, these containers utilize a vacuum-sealed airspace to create insulation.

When subjected to the high heat of both the wash and dry cycle of a dishwasher, this seal is broken- essentially rendering this item no longer able to insulate its contents. To give these items a long lifespan, wash them by hand.

Sieves

Because of the fine mesh used, sieves tend to hold onto food particles that go flying around your dishwasher. The metal is also prone to rust and the wet, hot environment of the dishwasher will ruin a sieve in no time.

Graters/Blades

Due to the sharp edges on graters, they should be washed by hand. Like knives, small nicks and dings can occur and cause damage to the sharp edges.

Blades from your food processor and blender aren’t quite as delicate. However, because they are most likely a mix of plastic parts and metal, they too will be damaged by the environment of the dishwasher.

Gold flatware

Unlike silver flatware, gold flatware will become dull and damaged if washed in the dishwasher. Flatware with colored coatings can also suffer damage, so if you have something other than the standard silver go ahead and wash it by hand.

Crystal

Beautiful and delicate, crystal is too precious to risk damage from the heat and water jets. While everyday wine glasses should fare fine, keep your crystal and fine drinking glasses out of the machine.

Milk Glass

Again as a culprit, the hot water and harsh detergents your dishwasher uses to make things sparkle are no good for milk glass. Milk glass is typically a beautiful white color, but a few washings in the dishwasher can turn it yellow.

Even other colors of milk glass are not safe, they all take on a murky, yellow shade when exposed to the dishwasher.

Metallic Trimmed China

The beautiful, delicate edges of china will, unfortunately, flake away if put into the dishwasher. Images that appear on fine china may also be damaged because of the hot water and harsh detergents.

Hand Painted Items

Even when these items are glazed and sealed, there is still a big risk of losing hand-painted works to the dishwasher. Wash carefully by hand and dry immediately to preserve these pieces.

Customized Mugs

You’ve probably gotten one as a gift or even bought one for yourself. With so many crafters creating custom mugs, you can pick practically anything and have it made just for you.

Typically a type of permanent vinyl is used to create these designs. Most sellers will send instructions to hand wash only and avoid soaking. While the vinyl uses a strong adhesive, the heat and moisture of the dishwasher will completely wipe out a design in one cycle.

Vintage Items

Unless you have specific cleaning instructions for an older item, don’t risk placing it in your dishwasher. You run the risk of chipping, cracking, and significant damage if the vintage item in question can’t hold up to the modern machines.

Repaired Dishes

Sure, you were able to glue all the pieces of your favorite mug back together after the cat knocked it off the table. However, you will now be washing that precious item by hand. High heat and adhesives are not a good mix, the dishwasher is bound to ruin your repair job right away.

Certain Plastics

Reusing plastic containers from the deli or grocery store is a great way to cut down on one-use plastic. But these are generally made with thin plastics that are sure to warp from the heat and water pressure of a dishwasher.

Acrylic Dishes

These dishes are durable and cute, perfect for kids and adults alike. However, the fun patterns and designs won’t last long if they are washed in the dishwasher.

Small cracks will also start to form in acrylic dishes as well as the heat from both the washing and drying cycle cause the material to become brittle and warp.

Paper & Printed Labels

While it may seem obvious that a paper label won’t survive either hand or machine washing, there is another factor to consider before popping that pickle jar in the dishwasher in hopes of saving time scrubbing the label off.

Bits of paper and adhesive will get stuck in the water system and mechanics of your dishwasher, so remove all labels prior to washing.

Printed on items such as measuring cups will lose their markings over time in the dishwasher. It doesn’t do you any good to have measuring cups with no measurements on them, so wash these by hand.

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Robin

Robin is in his 30s and still enjoys the things he enjoyed as a teenager. He has studied nutrition, personal training, coaching, and cooking. He has an ever-growing interest in the art of cooking the best burger in the world. Thankfully, he also loves going to the gym.

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