15 Things You Should Never Put in the Dishwasher

While dishwashers offer a convenient way to clean up after meals (raise your hand if doing the dishes is your least favorite chore), they're not a one-size-fits-all solution for every kitchen item. The combination of intense heat, powerful water jets, and abrasive detergents can damage or degrade certain materials and finishes. 

Knowing which items to keep out of the dishwasher not only helps them remain functional and looking their best, but also prolongs their lifespan — saving you time and money in the long run. (And don't forget to periodically clean your dishwasher.)

Here are 15 items you should never place in the dishwasher. 

Since wooden items absorb water, placing them in the dishwasher can cause them to swell and potentially crack or warp. The high temperature in the dishwasher can also strip away natural oils, resulting in dryness and brittleness. When it comes to items made from wood, it's best to hand-wash and periodically oil them to maintain their quality and prolong their lifespan. 

Cast-iron pans are seasoned with oil to create a natural, non-stick surface that is best used for high-temperature searing and grilling. Dishwashers can strip away this seasoning and expose the iron to moisture, which can lead to rusting. Hand-washing the cast-iron skillet and re-seasoning as needed will preserve your pan's functionality and appearance.

Related: Cast Iron vs. Stainless Steel: Which Pan Should You Cook With?

The abrasive nature of dishwasher tablets and high water pressure can deteriorate a pan's non-stick coating. Over time, this can make it less effective and eventually cause the coating to flake into food. To best preserve the integrity of the pan's non-stick surface, hand wash it with dish soap and warm water. 

Sharp edges can become dulled when they come in contact with high forces of water and other items while in the dishwasher. Furthermore, high-quality knife handles can deteriorate or warp due to moisture and heat. To maintain your knives' sharpness and handle quality, it's best to hand-wash knives and let them air dry. 

Related: The Best Kitchen Knife Sets You Can Buy on a Budget

Crystal is a delicate material that can easily crack, chip, or become cloudy with exposure to harsh soaps and high heat. The intense water jets can also cause fragile pieces to collide and break. Hand-washing with a gentle dish soap ensures the longevity and clarity of crystal and glassware items.

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The chemicals in dishwasher detergents can tarnish plates and utensils that have a gold trim or other designs painted on them. Over time, this could lead to fading or complete removal of the details. Our advice? If something looks fragile and expensive, such as a family heirloom, keep it out of the dishwasher and opt for hand-washing. 

Related: 25 Products to Upgrade Your Kitchen for Cheap

Exposure to extreme heat coupled with dishwasher soap can discolor copper and brass, resulting in a tarnished or dull appearance. The high heat can also warp or distort these metals. To best maintain their natural shine, it's best to handwash and polish as necessary.

Related: This TikTok Grandma Just Taught Us a Brilliant Dishwasher Hack

These thin materials can easily warp or twist under the dishwasher's heat. They might discolor other items through the transfer of aluminum residue; some plastics can also release harmful chemicals when exposed to high temperatures. 

If your parents are like mine and yell at you for throwing out plastic containers even when they're stained with spaghetti sauce, remind them that these items are disposable and not meant to last forever. 

If you do want to clean your plastic containers and hang onto them for a bit longer, there are still several ways to get stains out of Tupperware.

Fine china often features delicate patterns and materials that can fade or chip when subjected to the intense heat of a dishwasher. Harsh detergents can also degrade fragile glazes and finishes. To keep china pristine for years to come, it's recommended to wash these pieces by hand and gently patting them dry. 

These water bottles have a vacuum seal that can become damaged in a dishwasher, eventually losing their insulating properties or breaking altogether. The outer appearance can also deteriorate with repeated harsh washing. When it comes to insulated water bottles like Yeti or Hydroflask, mugs, and tumblers, hand washing is always your best option. 

The force of water and strong detergents can chip or fade hand-painted designs as the protective layer gets stripped. Certain materials used in pottery might also not be able to withstand the heat, which can lead to cracks or chips. When it comes to ceramic dishes and pots, it's best to hand wash them gently to preserve their appearance and structure.

Related: Here’s Why Dishwasher Tablets Are a ‘Scam,’ According to Redditors

Repeated exposure to the dishwasher's heat and chemicals can degrade rubber seals and loosen screws on a pressure cooker — eventually affecting the cooker's efficiency and shortening its lifespan. Over time, this could lead to unsafe cooking conditions if the lid is not functioning properly. Hand-washing the lid and seals can help prolong their efficacy.

Graters and fruit peelers have small nooks where food residue can hide and not be cleaned effectively in a dishwasher. Leftover particles can then become a breeding ground for bacteria or mold. Hand-washing and using a small scrub to get into all the nooks and crannies ensures thorough cleaning of these kitchen items. 

Fine stemware is delicate and can break or become weakened in a dishwasher, especially the slender stems of certain wine glasses and flutes. The abrasive detergents can also dull the clarity of the glass. Gently washing them by hand keeps them looking pristine and can help prolong their lifespan. 

Air fryer baskets often have a non-stick coating to ensure food doesn't adhere to them during the cooking process. Placing them in the dishwasher can deteriorate this coating over time. Furthermore, tiny food particles can get lodged in the basket's mesh, leading to incomplete cleaning. For best results, hand-wash the basket and use disposable filters to maintain your air fryer's efficacy and keep it running at its best.

And remember, there are also some foods that you should never cook in an air fryer.