How to Clean Cast Iron
For routine cleaning, wipe out the pan and wash it by hand when necessary.
Dry it thoroughly afterward.
If your cookware manufacturer provides specific cleaning instructions, follow those recommendations.
4. Carbon-Steel Cookware
Carbon steel has many of the same concerns as cast iron.
It's typically seasoned, and repeated dishwasher exposure can interfere with that seasoning and leave the surface vulnerable to rust.
Hand washing is generally the better choice.
Dry the pan thoroughly after cleaning and maintain the seasoning according to the manufacturer's instructions.
5. Copper Cookware
Copper cookware is beautiful—and it deserves a little extra attention.
Dishwasher detergents and repeated exposure to heat and water can cause copper surfaces to become dull, discolored, or otherwise damaged.
If you have expensive copper pots or pans, check the manufacturer's cleaning instructions before putting them anywhere near the dishwasher.
What About Copper-Colored Cookware?
This is where things get interesting.
Something that looks like copper isn't necessarily solid copper.
It may have a stainless-steel body with a copper-colored coating or finish.
In that case, the manufacturer's instructions are especially important.
Don't judge dishwasher safety based solely on appearance.
6. Fine Crystal
Fine crystal glassware can be much more delicate than ordinary drinking glasses.
High temperatures, strong water jets, detergent, and contact with other dishes can increase the risk of scratching, chipping, or breaking.
Some crystal can also become cloudy or etched after repeated dishwasher cycles.
If the glassware is precious, antique, especially thin, or specifically labeled hand-wash only, washing it by hand is the safer choice.
7. Antique or Vintage Dishes
That beautiful dish you inherited from your grandmother?
I would think twice before putting it in the dishwasher.
Vintage dishes may have delicate decorations, painted details, metallic trim, old glazes, or materials that weren't designed for modern dishwasher conditions.
Even if something has survived beautifully for decades, repeated dishwasher cycles may gradually damage it.
A Good Rule for Treasured Pieces
If you would be genuinely upset if something happened to it, wash it by hand.
That's probably the simplest rule of all.
8. Anything With Gold or Metallic Trim
Those beautiful plates with gold rims may look perfectly sturdy.
But decorative metallic details can be vulnerable to repeated dishwasher exposure.
Over time, the finish may fade, wear away, or lose its shine.
The same caution applies to dishes decorated with silver-colored or other metallic accents.
If you want those details to stay beautiful, hand washing is generally the safer choice.
9. Nonstick Cookware That Isn't Labeled Dishwasher-Safe
Nonstick coatings aren't all the same.
Some manufacturers specifically design certain nonstick cookware to tolerate dishwasher cleaning.
Others recommend hand washing.
That's why you shouldn't assume every nonstick pan is dishwasher-safe.
Repeated exposure to high temperatures, strong detergent, and aggressive cleaning can shorten the life of some coatings.
Check the Manufacturer's Instructions
If the pan is labeled dishwasher-safe, follow the instructions.
If it's labeled hand wash only, believe the label.
And even when dishwasher cleaning is technically allowed, gentle hand washing may help some cookware last longer.
10. Knives With Sharp Blades
Some kitchen knives are technically dishwasher-safe.
That doesn't necessarily mean the dishwasher is the best place for them.
Sharp knives can become damaged by knocking against other utensils or racks.
The blade can also become duller over repeated cycles depending on the knife and dishwasher setup.
There's another issue too: safety.
A sharp knife sitting point-up in a dishwasher basket is an unnecessary hazard when you're unloading the machine.
The Better Option
Wash quality kitchen knives by hand with care.
Dry them promptly and store them safely.
11. Insulated Travel Mugs
This one catches people by surprise.
Some insulated travel mugs are dishwasher-safe.
Others are not.
The problem is that insulated cups often contain multiple components, seals, coatings, or vacuum-insulated sections that can react differently to dishwasher heat.
A dishwasher cycle may damage the finish or seals on products that aren't designed for it.
Always Check the Label
Look at the manufacturer's care instructions for your specific mug.
And don't assume that because the cup itself seems sturdy, every removable part should automatically go in the dishwasher.
Lids and silicone seals may have their own care requirements.
12. Items With Delicate Seals or Moving Parts
Some kitchen gadgets contain rubber gaskets, silicone seals, springs, bearings, or other small components.
Dishwasher heat and detergent may affect those materials over time.
This can include certain:
- Specialty bottles
- Food storage containers
- Coffee equipment
- Kitchen gadgets
- Blender components
- Pressure-cooker parts
Again, the manufacturer's instructions are your friend.
If a product has several moving or sealing components, don't assume every piece belongs in the dishwasher.
13. Wooden-Handled Knives and Tools
A knife with a wooden handle can have two different materials that respond very differently to dishwasher conditions.
The wood may swell or crack.
The handle may become loose.
Adhesives or fasteners can also deteriorate over time.
Even if the metal blade itself is dishwasher-safe, the handle may not be.
Wash these by hand unless the manufacturer specifically says otherwise.
14. Certain Aluminum Cookware
Aluminum is another material where dishwasher compatibility depends heavily on the specific product and finish.
Some aluminum cookware can become discolored or develop a dull appearance after repeated dishwasher exposure.
Certain detergents can react with aluminum surfaces.
This doesn't mean all aluminum cookware must stay out of the dishwasher.
It means you should check the manufacturer's instructions rather than making a blanket assumption.
15. Anything Labeled "Hand Wash Only"
This sounds obvious, but it's worth saying.
If the manufacturer has specifically written "hand wash only," don't treat it as a suggestion.
Manufacturers know how their materials, coatings, adhesives, seals, and finishes are designed to perform.
A dishwasher may save you five minutes today but shorten the life of the item significantly.
What About Plastic?
Plastic is a little more complicated.
Some plastics are absolutely dishwasher-safe.
Others can warp, discolor, or degrade.
And some plastic containers simply aren't designed to tolerate the heat of the dishwasher's hottest areas.
Look for the Dishwasher-Safe Symbol
If a plastic container is labeled dishwasher-safe, follow the manufacturer's placement instructions.
Some items should go only on the top rack because the lower rack is generally exposed to more heat.
And if there is no care information at all, hand washing is often the more cautious choice for delicate or thin plastic.
What About Silicone?
Many silicone kitchen products are dishwasher-safe, but again, it depends on the item.
Silicone baking molds, spatulas, and storage products are often designed to tolerate heat, but products can differ.
Check the manufacturer's instructions, especially if the silicone item contains another material such as wood, metal, or an adhesive component.
Items That Can Actually Damage Your Dishwasher
Most dishwasher mistakes simply damage the item you're washing.
But a few objects can cause problems for the dishwasher itself.
Items With Loose Food Debris
Scrape dishes before loading them.
You don't necessarily need to pre-rinse every dish, but large pieces of food should be removed.
Large debris can collect in the filter or interfere with proper drainage.
Items That Can Block the Spray Arms
Before starting the machine, make sure tall utensils, pans, or other objects aren't positioned where they can prevent the spray arms from rotating freely.
A dishwasher can't clean properly if the water jets can't reach the dishes.
The Top Rack Isn't a Magic Safety Zone
You've probably heard the rule:
"If you're worried, just put it on the top rack."
Sometimes that's useful.
But the top rack doesn't magically make a non-dishwasher-safe item dishwasher-safe.
It may expose an item to somewhat different heat and water conditions, but the item still has to be designed for dishwasher use.
Always follow the product's care instructions.
How to Tell If Something Is Dishwasher-Safe
Before putting a questionable item in the machine, check:
Look at the Bottom
Some products have care symbols or instructions printed or molded onto the bottom.
Check the Packaging
If you still have the original packaging, look for cleaning instructions.
Search the Manufacturer's Instructions
For branded cookware, mugs, appliances, and specialty kitchen tools, the manufacturer's care information is usually the most reliable source.
Consider the Material
Wood, fine crystal, uncoated cast iron, and delicate decorative finishes deserve extra caution.
But material alone isn't always enough to determine dishwasher safety.
A Simple Dishwasher-Safety Checklist
Before you load that questionable item, ask yourself:
Is it made of wood?
Does it have a delicate coating?
Does it contain a metallic finish?
Is it vintage or valuable?
Does it have a sharp blade?
Does it contain seals or moving parts?
Does it have a delicate handle?
Does the manufacturer say "hand wash only"?
If you answered yes to any of those, take a moment to check the care instructions.
That tiny pause could save you from a cracked cutting board, ruined finish, or expensive replacement.
Frequently Asked Questions
Can wooden spoons go in the dishwasher?
It's generally better to wash wooden spoons by hand. Repeated exposure to dishwasher heat, water, and detergent can contribute to cracking, splitting, warping, or deterioration.
Can cast iron go in the dishwasher?
Traditional seasoned cast iron should generally be hand-washed. Dishwasher cleaning can strip seasoning and promote rust.
Can stainless steel go in the dishwasher?
Many stainless-steel items are dishwasher-safe, but not every stainless-steel product is identical. Check the manufacturer's instructions, especially if the item has a coating, decorative finish, or attached components made from another material.
Can knives go in the dishwasher?
Some knives are labeled dishwasher-safe, but hand washing is often preferable for quality kitchen knives because it can help protect the blade and handle and avoids having sharp objects loose in the dishwasher.
Can plastic containers go in the dishwasher?
Many can, but check the label. Some plastics can warp or become damaged by dishwasher heat. Dishwasher-safe plastic may also have specific rack-placement instructions.
Why shouldn't wooden cutting boards go in the dishwasher?
The combination of hot water, prolonged moisture, detergent, and drying heat can cause wood to swell, warp, crack, or split.
Can nonstick pans go in the dishwasher?
Some are dishwasher-safe and others are not. Follow the manufacturer's instructions. Even when dishwasher cleaning is permitted, gentle hand washing may help extend the life of some nonstick cookware.
Can glass go in the dishwasher?
Ordinary sturdy glassware is often dishwasher-safe. Fine crystal, delicate glass, antique pieces, and glasses with decorative finishes may require hand washing.
Is the top rack safer than the bottom rack?
For some dishwasher-safe items, yes—the manufacturer may specifically recommend the top rack. But putting an item on the top rack does not automatically make it dishwasher-safe.
The Bottom Line
The dishwasher is absolutely one of the greatest kitchen conveniences.
But it isn't a universal cleaning machine for every object in your kitchen.
Wood, traditional cast iron, delicate crystal, vintage dishes, metallic decorations, certain nonstick cookware, quality knives, and many specialty items deserve a little more attention.
And here's the easiest rule to remember:
If you aren't sure, check the manufacturer's instructions before pressing Start.
It takes less than a minute.
That's a pretty good trade when the alternative could be a warped cutting board, ruined finish, rusty skillet, or your favorite kitchen treasure coming out of the dishwasher looking like it had a very bad day.
So load those everyday plates.
Let the dishwasher do the heavy lifting.
Just give the questionable items a second look first.
Your future self—and your favorite kitchenware—will probably thank you.
