A dishwasher can save a lot of time, but there are a few kitchen favorites that are worth giving a little extra attention.
The problem isn’t that a dishwasher is “bad” for everything. It’s that heat, detergent, water pressure, and repeated washing can be hard on certain materials and finishes.
Cast iron can rust, wooden utensils can warp, delicate glass can break, and some cookware coatings can wear faster.
And there’s one rule that’s more important than any list you’ll find online:
If the manufacturer says an item is dishwasher-safe, follow the manufacturer’s instructions.
With that in mind, here are eight kitchen items that are often better washed by hand.
1. Cast-Iron Cookware
Cast iron is wonderfully durable, but regular dishwasher cycles can work against the very finish that makes a seasoned skillet so useful.
The combination of prolonged water exposure and dishwasher detergent can remove seasoning and leave the iron vulnerable to rust. Whirlpool specifically lists cast iron as not dishwasher-safe, noting that seasoning can be removed and the iron can rust.
Better way to clean it
For everyday cleaning:
- Let the pan cool enough to handle safely.
- Wash it with warm water.
- Use a small amount of mild dish soap if needed.
- Scrub away stuck-on food with a suitable brush or scrubber.
- Dry it thoroughly.
If your pan’s care instructions recommend it, finish by rubbing on a very thin layer of cooking oil.
The most important part is simple:
Don’t put a wet cast-iron pan away.
Moisture left on the surface is an invitation for rust.
2. Good Kitchen Knives
Your dishwasher may make a knife clean, but that doesn’t mean it’s the best place for it.
Sharp knives can knock against other utensils during a cycle, and repeated exposure to heat and detergent can be hard on certain handles, finishes, and construction.
Some hollow-handle knives can have adhesive components that are affected by dishwasher conditions. Whirlpool specifically recommends hand washing knives.
Better way to clean them
Wash a good knife by hand with:
- Warm water
- Mild dish soap
- A soft sponge
Then dry it immediately.
And please don’t reach blindly into a sink full of soapy water looking for a knife.
Wash it while you can see where the blade is, and store it safely afterward.
A few seconds of careful hand washing is much easier than dealing with a damaged blade—or an injured hand.
3. Wooden Spoons and Cutting Boards
Wood and long exposure to water are not a great combination.
Repeated dishwasher cycles can cause wood to absorb moisture and then dry out again. Over time, that repeated expansion and contraction can contribute to warping, cracking, or splitting.
Whirlpool recommends hand washing wooden ware and notes that untreated wood can warp or crack.
Better way to clean wood
Wash wooden utensils and cutting boards promptly after use with warm, soapy water.
Avoid leaving them submerged in the sink.
After washing, dry them with a towel and let them air-dry completely before putting them away.
For wooden cutting boards, follow the manufacturer’s instructions for conditioning. A food-safe board conditioner may be recommended from time to time.
And don’t wait until a wooden board is visibly dry and cracked before giving it some care.
4. Delicate Glassware and Crystal
Your everyday drinking glasses are often perfectly fine in the dishwasher.
Your grandmother’s delicate crystal stemware is another story.
Thin glass, delicate stems, decorative finishes, and certain types of crystal can be more vulnerable to chips, breakage, scratching, or surface damage during repeated dishwasher cycles.
Whirlpool recommends hand washing fine china and crystal or delicate glassware, while noting that some crystal may be affected by repeated dishwasher washing.
Better way to clean delicate glasses
Put a folded towel or soft sink mat in the bottom of the sink.
Wash one piece at a time with warm water and mild dish soap.
Don’t squeeze a delicate stem tightly.
And when drying, support the bowl rather than twisting the stem.
That little bit of caution is especially worthwhile for glasses that are difficult—or expensive—to replace.
5. Copper and Brass Cookware
Copper cookware is beautiful, but some copper and brass pieces don’t react well to dishwasher conditions.
High temperatures and detergent can cause discoloration, tarnishing, or even damage to certain finishes. Whirlpool specifically lists brass and bronze among materials that can discolor or pit in the dishwasher.
Better way to clean them
For copper or brass pieces that aren’t labeled dishwasher-safe, hand wash them with warm water, mild dish soap, and a soft cloth or sponge.
If the cookware has a special finish or a lined interior, follow its specific care instructions.
Don’t assume that every copper pan should be polished the same way.
The finish and construction matter.
6. Nonstick Cookware
This one needs an important qualification.
Not every nonstick pan has to be hand washed.
Some modern cookware is specifically labeled dishwasher-safe. Cuisinart, for example, sells nonstick cookware that is dishwasher-safe, while other cookware lines are not.
So the best advice isn’t “never put nonstick in the dishwasher.”
It’s:
Check the care instructions for your particular pan.
If the manufacturer recommends hand washing, use warm water, mild dish soap, and a soft sponge.
Avoid steel wool, abrasive scrubbers, and anything else that could scratch the cooking surface.
Even when a pan is technically dishwasher-safe, hand washing may help preserve its finish longer. Cuisinart notes that repeated dishwasher cycles can shorten the life of some cookware finishes.
7. Soft Plastic Containers and Questionable Plastics
This is another category where appearances can be misleading.
Two plastic containers may look almost identical, yet one may be designed for dishwasher temperatures while the other may warp.
Thin lids, flexible seals, and lightweight containers can be particularly vulnerable to heat.
Whirlpool notes that heated-dry cycles can reach temperatures that some plastics cannot tolerate, even when other plastics are dishwasher-safe.
What to do
Look for the dishwasher-safe symbol or check the manufacturer’s instructions.
If the container is approved for dishwasher use, follow the recommended rack placement.
If you’re unsure, hand washing is the safer choice.
And if a plastic container has already started to warp, crack, or change shape, it’s probably time to replace it rather than hoping the next cycle will somehow fix it.
8. Insulated Travel Mugs and Tumblers
This is one of those items many people throw into the dishwasher without thinking twice.
But an insulated tumbler isn’t simply a cup.
Depending on the design, it may contain a vacuum-insulated body, seals, gaskets, painted finishes, adhesives, or other components that require specific care.
Some are dishwasher-safe.
Some aren’t.
So this is a category where the manufacturer’s instructions matter more than a general rule.
If hand washing is recommended
Take the lid apart as much as the manufacturer allows.
Remove the gasket or seal if it’s designed to be removed.
Wash each part thoroughly and let everything dry completely before putting it back together.
This is particularly important because moisture trapped underneath a lid seal can become a source of unpleasant odors.
