Things You Should Never Put in the Dishwasher
If you’re anything like me, you love the convenience of a dishwasher. After a long day, there’s something incredibly satisfying about loading it up, pressing a button, and letting the machine handle the dirty work.
But here’s the catch: not everything belongs in the dishwasher.
Putting the wrong items inside can do more than damage your favorite kitchen tools. High temperatures, powerful water jets, and strong detergents can cause warping, rust, discoloration, dullness, and even permanent damage to delicate finishes.
The good news? A little extra care can go a long way.
The golden rule is simple: when in doubt, check the manufacturer’s instructions. If an item is labeled “hand wash only,” it’s best to believe it. Dishwasher conditions are considerably more intense than washing something gently by hand.
Here are some of the most common kitchen items that deserve a little more attention.
1. Sharp Knives and Wooden Utensils
Sharp kitchen knives might seem like an obvious candidate for the dishwasher, but they’re actually better off being washed by hand.
The powerful water jets can cause knives to knock against other dishes, gradually dulling their edges. Dishwasher detergents and high temperatures can also damage wooden handles, causing them to crack, warp, or loosen over time.
There’s another issue that’s easy to overlook: safety. Reaching into a dishwasher filled with dishes and hidden knife blades can result in an accidental cut.
How to care for them
Wash knives and wooden utensils by hand using warm, soapy water. Dry them immediately afterward to prevent moisture-related damage and, in the case of certain steel knives, rust.
Store knives safely in a knife block, protective sheath, or magnetic strip. Wooden utensils can occasionally benefit from a food-safe mineral oil to keep the wood from drying out.
Even if a knife is technically labeled dishwasher-safe, hand washing is generally gentler and can help preserve its edge and finish.
2. Delicate Crystal and Fine China
If you have beautiful crystal glasses or fine china tucked away for special occasions, the dishwasher may not be the best place for them.
Powerful water jets can cause fragile glass to knock against other items, resulting in chips or cracks. Heat and detergents can also contribute to clouding or etching on some types of crystal.
And if your fine china features gold, silver, or decorative trim, repeated dishwasher cycles may cause the detailing to fade or deteriorate.
How to care for them
Wash delicate pieces gently in lukewarm water with mild dish soap. A towel placed at the bottom of the sink can provide some extra protection against accidental knocks.
Rinse carefully and dry with a soft, lint-free cloth. Avoid stacking heavy dishes on top of delicate china.
3. Cast-Iron Cookware
Cast iron is one of the most durable materials in the kitchen—but that doesn’t mean it loves the dishwasher.
The problem is the seasoning: the layer of baked-on oil that helps protect the pan and gives it its characteristic cooking surface. Strong detergents and prolonged exposure to water can strip away this protective layer and leave the iron vulnerable to rust.
How to care for it
Allow your cast-iron cookware to cool slightly, then clean it by hand with hot water and a stiff brush or suitable scrubber.
Dry it thoroughly. One easy method is to place the pan over low heat on the stove for a few minutes to evaporate any remaining moisture.
Once completely dry, apply a very thin layer of cooking oil to help maintain the seasoning.
Avoid leaving cast iron submerged in water for extended periods.
4. Nonstick Cookware
Nonstick pans are designed to make cooking and cleaning easier, but that doesn’t necessarily mean they belong in the dishwasher.
Repeated exposure to high temperatures and aggressive detergents can accelerate wear on nonstick coatings. Over time, the surface may lose its effectiveness and the cookware may need to be replaced sooner.
How to care for it
Let the pan cool before washing it by hand with a soft sponge and mild dish soap.
Avoid abrasive scrubbers, steel wool, and anything that could scratch the cooking surface.
Some modern nonstick and ceramic-coated pans are marketed as dishwasher-safe, so always follow the manufacturer’s instructions. However, gentle hand washing is often the better choice if you want to maximize the lifespan of your cookware.
5. Anything With Adhesive Labels
We’ve all been there: you put a jar, dish, or container in the dishwasher and discover afterward that the label has transformed into a sticky mess.
Heat and water can loosen labels and break down adhesives. The result can be paper fragments and stubborn glue stuck to your dishes or dishwasher components.
How to care for them
Remove labels and stickers before putting the item in the dishwasher.
For stubborn adhesive, soak the item in warm, soapy water. Once the label has softened, gently remove the remaining residue with a suitable scraper or cloth.
It’s a small step that can save you a surprisingly frustrating cleanup later.
6. Insulated Travel Mugs and Thermoses
Your favorite insulated travel mug may keep your coffee hot for hours, but that doesn’t mean it should automatically go into the dishwasher.
Some insulated containers rely on vacuum seals between their walls. Repeated exposure to high temperatures may affect certain seals or components. Plastic lids and rubber gaskets can also wear out or deform over time.
How to care for them
Check the manufacturer’s instructions first, as some modern insulated products are specifically designed to be dishwasher-safe.
If you’re unsure, wash the mug by hand using warm, soapy water. A bottle brush can help reach the inside, while removable lids and seals should be cleaned separately.
Allow everything to dry completely before reassembling the mug, particularly around rubber seals and other areas where moisture can become trapped.
7. Copper Cookware
Copper cookware can add a beautiful touch to any kitchen, but it requires more careful handling than many everyday pots and pans.
Dishwasher detergents and high temperatures can cause copper surfaces to tarnish or discolor. In some circumstances, repeated exposure may also contribute to corrosion or other surface damage.
How to care for it
Wash copper cookware by hand with warm water and mild soap. Dry it promptly to reduce water spots and maintain its appearance.
If the copper becomes tarnished, use a cleaner specifically designed for copper and follow its instructions.
If your cookware has a special lining or finish, always follow the manufacturer’s cleaning recommendations.
8. Old or Valuable China
Family heirlooms and antique dishes deserve special treatment.
Older china can be more fragile than modern tableware, and repeated exposure to heat, strong detergents, and powerful water jets may damage delicate decorations or finishes.
Hand-painted patterns, gold details, and other decorative elements can be particularly vulnerable.
How to care for it
Wash valuable or antique china by hand using lukewarm water, mild soap, and a soft sponge or cloth.
Avoid abrasive cleaners and sudden temperature changes. Dry each piece carefully and store it somewhere secure where it won’t be knocked against other dishes.
When it comes to irreplaceable family pieces, a few extra minutes of hand washing are well worth it.
Common Dishwasher Mistakes to Avoid
Knowing what not to put in the dishwasher is only half the battle. Even dishwasher-safe items can come out dirty or damaged if the machine isn’t used properly.
Here are a few common mistakes to avoid:
- Overloading the dishwasher: Crowding dishes can prevent water and detergent from reaching every surface.
- Pre-rinsing everything: In many modern dishwashers, simply scraping off large food particles is enough. Excessive pre-rinsing can be unnecessary.
- Using regular dish soap: Never substitute hand-washing dish soap for dishwasher detergent. The resulting foam can overflow from the machine.
- Ignoring the filter: A dirty filter can reduce cleaning performance. Check your owner’s manual for instructions on how and how often to clean it.
- Forgetting rinse aid: If your dishwasher supports rinse aid, using it can help reduce water spots and improve drying performance.
One more important tip: follow your dishwasher manufacturer’s maintenance instructions. Cleaning methods vary between machines, and some commonly suggested hacks aren’t suitable for every appliance.
Frequently Asked Questions
Can I put wooden spoons in the dishwasher?
It’s generally better to wash wooden spoons by hand. Prolonged exposure to heat and moisture can cause wood to dry out, crack, warp, or split.
Are all nonstick pans dishwasher-safe?
No. Some are labeled dishwasher-safe, while others are not. Check the manufacturer’s instructions for your specific pan.
Why shouldn’t I put cast iron in the dishwasher?
Dishwasher detergents and prolonged exposure to water can strip away seasoning and increase the risk of rust.
What happens if I accidentally put a knife in the dishwasher?
One cycle may not ruin the knife, but repeated dishwasher washing can dull the blade and damage certain handles. Remove it carefully and hand wash it from then on.
Is fine china always unsafe for the dishwasher?
Not necessarily. Some modern fine china is dishwasher-safe. However, antique, hand-painted, or gold-trimmed pieces often require more careful handling.
Final Thought: Take Care of Your Kitchen Tools
Your kitchen tools are more than just objects you use every day. Some are investments, some are heirlooms, and others simply become favorites over years of cooking.
The dishwasher is an incredibly useful appliance, but it’s not a magic box that can safely clean everything.
Knowing which items need a little extra attention can help prevent unnecessary damage and extend the life of the things you use most.
So the next time you’re tempted to toss a wooden spoon, sharp chef’s knife, cast-iron skillet, or treasured piece of china into the dishwasher, take a second look.
Sometimes, a few minutes of careful hand washing can save you from an expensive replacement later.
Take care of your kitchen tools, and they’ll take care of you for years to come.
You’ve just read Things You Should Never Put in the Dishwasher. Why not read The Mysterious Tool That Had the Internet Guessing