Things You Absolutely Should Not Put in a Dishwasher: 8 Items to Hand-Wash Instead

Your chef's knife might be one of the most frequently used tools in your kitchen, but it generally deserves more care than an ordinary dinner knife.

Although some kitchen knives are labeled dishwasher-safe, hand-washing sharp, high-quality kitchen knives is usually the better choice.

Why the dishwasher can damage them

Dishwasher detergents can be abrasive, and repeated exposure to hot water and moisture may contribute to corrosion or discoloration, especially on certain types of steel.

Knives can also bump against other utensils during a wash cycle, potentially damaging their edges. Wooden handles may swell, crack, or loosen with repeated exposure to heat and water.

A dull knife isn't just inconvenient. It can also be harder to control when cutting food.

How to clean knives safely

Wash sharp knives individually with warm water, a small amount of dish soap, and a soft sponge. Keep the blade pointed away from your hands, rinse it carefully, and dry it immediately.

Avoid leaving knives loose in a sink full of soapy water, where someone could accidentally reach onto the blade.

The bottom line: A quick hand-wash helps protect the blade, handle, and overall performance of your favorite kitchen knife.

2. Cast-Iron Pans and Skillets

Cast-iron cookware is loved for its durability, heat retention, and ability to develop a naturally slick cooking surface when properly seasoned.

But even though cast iron is built to last, the dishwasher is not its friend.

Why the dishwasher can damage cast iron

A well-seasoned cast-iron pan has a protective layer created by polymerized oil. This seasoning helps protect the metal from rust and contributes to its cooking performance.

Hot water, detergent, and prolonged moisture can damage that layer, leaving the pan more vulnerable to rust.

You might open the dishwasher expecting a clean skillet and discover a dull, rusty-looking surface instead.

How to clean cast iron safely

For routine cleaning, wash the pan with warm water and a brush or nonabrasive sponge. A small amount of mild dish soap is generally fine for well-seasoned cast iron.

Dry the pan thoroughly, then apply a very thin layer of cooking oil if appropriate for its care instructions.

If the seasoning becomes damaged, it can often be restored with proper re-seasoning.

Remember: Traditional bare cast iron and enameled cast iron aren't identical. Follow the manufacturer's instructions for enameled cookware, since care requirements can vary.

3. Wooden Spoons, Cutting Boards, and Utensils

Wooden kitchen tools bring warmth and character to a kitchen. Wooden spoons, spatulas, and cutting boards are also useful because they are gentle on many cookware surfaces.

Unfortunately, repeated dishwasher cycles can be rough on wood.

Why the dishwasher can damage wood

Wood absorbs moisture and expands, then contracts as it dries. Repeated exposure to hot water and heated drying can encourage cracking, warping, splintering, or loosening at joints.

Wooden items may also lose their smooth finish and become rough over time.

Once a cutting board develops deep cracks or splits, cleaning it thoroughly can become more difficult.

How to clean wooden kitchen items safely

Wash wooden spoons and utensils by hand with warm water and mild dish soap. Rinse them promptly and dry them with a towel.

Allow cutting boards to air-dry completely in a position that allows air to circulate around them.

For wooden items that are becoming dry, an appropriate food-safe mineral oil or board conditioner may help maintain the surface. Follow the manufacturer's recommendations.

A little hand-washing goes a long way toward helping wooden kitchen tools last longer.

4. Copper Pots, Pans, and Decorative Cookware

Copper cookware is beautiful, conducts heat efficiently, and often serves as a decorative feature in the kitchen.

But if you want to preserve its appearance, it's generally best to keep it out of the dishwasher.

Why the dishwasher can damage copper

Dishwasher detergents and high temperatures can dull copper's shine, cause discoloration, and affect certain protective finishes.

The risks depend on the item. Solid copper, lacquered copper, and copper cookware with a stainless-steel lining may have different care requirements.

Repeated washing can be particularly hard on decorative copper pieces whose polished appearance is part of their appeal.

How to clean copper safely

Wash copper items by hand using warm water, mild dish soap, and a soft sponge. Dry them thoroughly with a clean cloth to help prevent water spots.

If the copper becomes tarnished, use a cleaning product specifically suitable for that item and follow its instructions. Avoid harsh abrasives that could scratch the finish.

If your cookware has a special coating or lining, check the manufacturer's care guidance before using any polishing product.

The bottom line: Hand-washing helps preserve the appearance and finish of copper cookware.

5. Fine China and Gold-Trimmed Dishes

Have a set of delicate china reserved for holidays, weddings, or special family dinners? Before loading it into the dishwasher, take a moment to check the care instructions.

Some modern porcelain and fine china are dishwasher-safe. However, older pieces, hand-painted dishes, and items with metallic decorations often need more careful handling.

Why the dishwasher can damage delicate china

Repeated exposure to detergent and heat can gradually wear away certain decorative finishes.

Gold or silver trim may lose its shine, while hand-painted designs can fade or become damaged. Delicate pieces can also chip if they knock against other dishes during the cycle.

Antique china may be particularly vulnerable because its materials, glazing, and decorative techniques can differ from those used in modern tableware.

How to clean fine china safely

If the manufacturer recommends hand-washing, use warm water, mild dish soap, and a soft sponge.

Wash each piece individually rather than stacking several delicate plates in the sink. Rinse carefully and dry with a soft towel.

For older or valuable china, avoid sudden temperature changes and abrasive cleaning tools.

When a dish has sentimental or financial value, it's worth taking the extra time to clean it gently.

6. Crystal Glassware and Delicate Drinking Glasses

Crystal glasses can make an ordinary dinner feel like a special occasion. Their clarity, weight, and decorative cuts give them an elegant appearance.

However, not every crystal glass is designed to withstand a dishwasher.

Why the dishwasher can damage crystal

High temperatures, detergent, and repeated washing can contribute to cloudiness or surface deterioration in some types of crystal and glassware.

Thin stems and delicate rims may also break if glasses vibrate or collide with other items during a cycle.

The problem isn't always immediate. Some glassware gradually loses its sparkle after repeated exposure to harsh washing conditions.

How to clean crystal safely

For delicate or valuable crystal, hand-wash using lukewarm water and a small amount of mild dish soap.

Support the glass by its bowl rather than twisting the stem, and avoid using very hot or very cold water.

Rinse gently and dry with a lint-free cloth.

Some modern crystal and decorative glassware are specifically labeled dishwasher-safe. If so, follow the manufacturer's directions, including any recommended cycle or rack placement.

If you're unsure, hand-washing is the safer option for delicate crystal.

7. Insulated Travel Mugs and Thermoses

Reusable travel mugs and insulated bottles are convenient for coffee, tea, water, and other drinks on the go.

But don't assume that a stainless-steel exterior means the entire container is dishwasher-safe.

Why the dishwasher can damage insulated drinkware

Some insulated mugs use a vacuum-sealed construction to keep drinks hot or cold. Others feature painted finishes, decorative coatings, seals, or lids with small components that may not tolerate high temperatures.

Dishwasher heat can damage certain finishes or affect seals. Some manufacturers also warn against dishwasher cleaning because of the way their particular products are constructed.

A damaged vacuum-insulated container may no longer maintain its temperature as effectively.

How to clean travel mugs safely

Check the manufacturer's instructions for the mug, bottle, and lid. Some products are dishwasher-safe, while others require hand-washing.

For hand-washing, use warm water, dish soap, and a bottle brush to reach the interior. Clean lids, straws, and removable seals separately, following the manufacturer's directions.

Allow all parts to dry completely before reassembling them.

One important detail: A dishwasher-safe lid doesn't necessarily mean the insulated body is dishwasher-safe, so check each component separately.

8. Nonstick Cookware

Nonstick pans make everyday cooking easier because food releases more readily from their coated surfaces.

However, repeated dishwasher washing can shorten the useful life of some nonstick cookware.

Why the dishwasher can damage nonstick pans

Dishwasher detergents, heat, and repeated washing can contribute to wear on certain nonstick coatings. Depending on the product, the exterior finish, handles, and other components may also be affected.

Some modern nonstick pans are labeled dishwasher-safe, but that doesn't necessarily mean dishwasher washing is the best way to preserve their coating over the long term.

Once a coating becomes badly worn or damaged, the pan may no longer perform as intended.

How to clean nonstick cookware safely

Allow the pan to cool before washing it. Use warm water, mild dish soap, and a soft sponge.

Avoid steel wool, abrasive scouring pads, and harsh cleaning products that can scratch or wear the coating.

Dry the pan thoroughly before storing it, and follow the manufacturer's recommendations for utensils, cooking temperatures, and cleaning.

For many nonstick pans, gentle hand-washing is the best way to help extend their lifespan.

A Few More Items to Check Before Loading the Dishwasher

The eight items above are worth special attention, but they're not the only things that may need to be kept out of the dishwasher.

Here are a few additional examples to check:

Uncoated aluminum: Certain aluminum items may discolor or develop a dull, darkened surface after dishwasher washing.
Pressure cooker components: Some lids, valves, gaskets, and electronic components require specific cleaning methods. Follow the manufacturer's instructions rather than assuming the whole cooker is dishwasher-safe.
Items with glued parts: Heat and moisture may weaken some adhesives.
Hand-painted mugs and decorative ceramics: Their finishes may not withstand repeated dishwasher cycles.
Items labeled hand-wash only: The manufacturer's instructions should take priority over general advice.

When shopping for kitchenware, look for clear care labels. A small symbol or instruction can save you from accidentally damaging an item you use every day.

How to Know Whether Something Is Dishwasher-Safe

If you're uncertain about a kitchen item, don't rely on appearance alone. A sturdy-looking mug or metal utensil may contain coatings, adhesives, or components that aren't designed for dishwasher use.

Use these simple checks before loading it into the machine.

1. Read the care label

Look for wording such as "dishwasher-safe," "top rack only," or "hand-wash only." If the product came with a manual, check that as well.

2. Check the manufacturer's website

If the label has worn off, search for the product's model name or number. The manufacturer may provide specific washing instructions.

3. Consider the materials

Wood, bare cast iron, delicate crystal, and certain decorative finishes generally deserve extra caution.

4. Separate the item from its accessories

A container, lid, gasket, handle, and removable insert may have different care requirements. Check each part separately.

5. Hand-wash when you're unsure

For valuable, delicate, or sentimental items, hand-washing is often the simplest way to reduce the risk of damage.

Common Dishwasher Mistakes to Avoid

Even dishwasher-safe items can be damaged when the machine is loaded or operated incorrectly.

Here are a few habits worth avoiding.

Overloading the racks

When dishes are packed too tightly, they can knock against each other during washing. This increases the risk of chips, cracks, and breakage.

Blocking the spray arms

Large plates, pots, or utensils can prevent water from circulating properly. Arrange items so the spray arms can rotate freely.

Using the wrong cycle

Some delicate items may require a gentle cycle or lower-temperature setting, if the manufacturer permits dishwasher cleaning.

Ignoring manufacturer instructions

A general rule of thumb can't replace the care guidance for a specific product. Always follow the item's instructions when available.

Leaving damp items stored away

Even after a wash cycle, some items may need additional drying. Make sure lids, seals, and other removable components are completely dry before reassembling and storing them.

Frequently Asked Questions

Can putting the wrong item in the dishwasher ruin it after one wash?

Yes, depending on the item. A wooden utensil might survive one cycle, while delicate glassware or a poorly secured item could break immediately. Other damage, such as coating wear or discoloration, may develop gradually over repeated washes.

Are all stainless-steel items dishwasher-safe?

No. Many stainless-steel utensils and dishes are dishwasher-safe, but some products have coatings, insulated construction, glued components, or other features that require special care. Check the manufacturer's instructions.

Is it okay to put nonstick pans in the dishwasher?

Some manufacturers label their nonstick pans dishwasher-safe. However, hand-washing with mild soap and a soft sponge is often a gentler way to maintain the coating.

Can wooden spoons go in the dishwasher if they're labeled as bamboo?

Don't assume so. Bamboo is a plant material, and repeated exposure to heat and moisture can still cause damage. Follow the care instructions for the specific utensil.

Why do glasses sometimes become cloudy in the dishwasher?

Cloudiness can result from mineral deposits, detergent residue, or permanent surface damage sometimes called glass corrosion or etching. The cause matters because mineral deposits may be removable, while etched glass generally cannot be restored to its original clarity.

Should I put sharp knives in the cutlery basket?

Even if a particular knife is dishwasher-safe, hand-washing is generally preferable for sharp kitchen knives. If a knife must be washed in a dishwasher according to its care instructions, load it securely and follow the manufacturer's safety guidance.

Are dishes marked dishwasher-safe guaranteed to last forever?

No. Dishwasher-safe means the item is designed to tolerate dishwasher cleaning under specified conditions. Repeated washing, incorrect loading, unsuitable detergents, and using the wrong cycle can still contribute to wear.

Final Thoughts: A Little Extra Care Can Save Your Favorite Kitchen Items

A dishwasher is a wonderful time-saver, but it isn't the right cleaning method for everything in your kitchen.

Sharp knives can lose their edge, cast iron can lose its seasoning, wood can crack, and delicate glassware or decorative finishes can become damaged over time. Certain insulated mugs and nonstick pans also need special attention, depending on their construction and care instructions.

The good news? Protecting these items doesn't have to be complicated.

Check the manufacturer's recommendations, hand-wash delicate pieces when needed, and give your favorite kitchen tools the care they deserve.

The next time you're about to load the dishwasher, take a quick look at what's going inside. That extra moment could help your kitchenware last longer and save you money on replacements.

Did you know about all eight of these dishwasher mistakes? Share this article with a friend or save it on Pinterest as a handy reminder for your next kitchen cleanup!