Everything that you should NEVER put in your dishwasher!

Researched & Written by Craig

Dishwashers are an invaluable way to save a countless amount of time washing dishes. However, we can’t just go throwing every single thing in there!

When it comes to appliances like these, it’s important to know what you should and shouldn’t be using them for. Don’t let your dishwasher cause you more problems than it solves!

Appliance Analysts’ Dishwasher ‘No-No’s’

#1 – Cast Iron Skillets

One of the fantastic aspects of a cast iron skillet is the build up of seasoning from repeated uses. Unfortunately, a dishwasher will destroy this foundation of flavour – and set the skillet all the way back to zero. (With some added detergent flavoring.)

Take care of your skillet with warm water and a light brush down instead. If there’s some stubborn leftovers, pour on a hearty pinch of salt and scour down the skillet with a kitchen cloth, before rinsing with hot water.

Cast iron skillet

Don’t do it.

#2 – Non-stick Pans

Similar to skillets, placing a non-stick pan in a dishwasher risks losing the main benefit: it’s non-stick coating. A gentle hand wash with warm water makes sure the non-stick coating will last. (Note: some non-stick pans are dishwasher-safe, but make sure this is stated by the manufacturer before risking it)

#3 – Wooden Utensils

Enduring the steaming hot water and drying can really warp wooden utensils; causing them to lose their smooth finish.

While this isn’t worth stressing over for cheap wooden spoons, any authentic or valuable wooden pieces should stay far away from a dishwasher.

#4 – High-quality knives

The harsh wash-cycle process and detergent from a dishwasher can actually dull a sharp knife. Plus, they’re also a bit of a hazard if you’re not careful when loading and unloading them. Instead, stick to just giving them a quick once-over by hand once you’re finished cutting.

Sharp kitchen knife


#5 – Knives with hollow-handles

The adhesive holding together a hollow-handled knife can be melted by hot dishwasher temperatures. Which can render the knife completely useless if it’s strength fails. Not to mention you probably don’t want the adhesive flowing down your drain!

#6 – Pressure cooker lids

The valves inside a pressure cooker lid can get clogged with small food particles. These are not only impossible to get out, but practically impossible to see, too. (Until the trapped pressure builds up to crazy levels, of course..)

#7 – China

One of the most well-known no-no’s, china dishes are far too fragile and valuable to risk. Not only that, but you may lose any hand-painted colors that are so unique to china pieces.

#8 – Crystal

Similarly, crystal is also too delicate for any standard dishwasher. Its brittleness means that it could chip or crack. Not worth the risk.

Crystal Port Glass


#9 – Anything copper

Dishwashing can dull the bright color that makes copper pieces so unique and attractive. The same goes for brass, bronze, or pewter dishes.

#10 – Anything gold plated

As beautiful as gold is, it’s quite soft and delicate. It can be damaged fairly easily, losing the quality look of a golden trim. Best to clean it softly by hand.


Don’t even think about it.

#11 – Anything Insulated

Anything with an insulation layer between the outer and inner walls (think large mugs and thermos flasks) shouldn’t go anywhere near a dishwasher. The hot water may find it’s way into the insulation layer, ruining the functionality of the contianer. A flask that can’t keep coffee warm for 5 minutes isn’t a very useful flask!

Thermos flask


#12 – Anything with labels/stickers

Want to keep that jam jar you picked up the local market? Just make sure to remove any labels and stickers before they get stuck in the drainpipe! Not to mention the adhesive, too.

#13 – Anything with printed measurements

When it comes to measuring cups or jugs which have their measurements printed on, it’s always best to just rinse them off by hand after use. Dishwasher detergent can fade these prints completely out, leaving you with a rather useless container.

#14 – Garlic press

Garlic presses are amazing timesavers, but can quickly cause more hassle than they save if you’re trying to clean them in the dishwasher. The small pieces of garlic can get lodged in the gaps, which will risk giving you some extra detergent-flavouring next time you use the press. Always aim to clean a garlic press right after you use it -it’s far easier. Even just a quick rinse with water does the job.

#15 – Cheese graters

Similar to garlic presses, a cheese grater won’t always end up ‘cheese-less’ at the end of a wash cycle. Rinse them after dinner by hand, or risk some of last weeks cheddar being added to your parmesan.

Cheese Grater

Can you guess..? (Hint: No!)

#16 – Most plastics

While it’s easy to assume that all plastics are dishwasher friendly, many aren’t. Always double check for a dishwasher-safe sign, before you open the door to melted plastic sealed to your dish rack!

#17 – Anything that would cause heartbreak if broken!

There’s some things that aren’t worth the risk to save a bit of time. Whether it’s a dish you’ve had for decades, or a unique piece from a local artisan, don’t risk losing it just to save a few minutes of cleaning.

If in doubt, get the sponge and cloth out!


While placing a garlic press in your dishwasher isn’t the end of the world, it’s important to know these things. There’s not much point having an appliance if it’s not saving you time, and causing you hassle instead!

Do you have any other ideas for something we may have missed out? Let us know in the comments!

Thanks for reading.

– The Appliance Analysts