6 Items That Are Definitely Not Dishwasher Safe — And How They Should Be Cleaned Instead

For many, dishwashers have revolutionized household chores, making cleaning up after a long day swifter. My partner can't live without his dishwasher, as it's so convenient, efficient, and easy compared to washing things by hand one at a time. But did you know that there are certain items you should avoid placing in this handy cleaning appliance?

It's not as simple as loading everything into your smart appliance and hitting go. Some items will not survive being placed in your dishwasher, and you could end up damaging them for good if you don't think twice about how you clean them.

Before the festive season commences, when dishes will seem endless, I spoke with a couple of professional cleaners to find out which items shouldn't pass through your dishwasher. Trust us, you'll be thanking us later for saving your home goods.

1. Wooden utensils

Wooden utensils may seem sturdy, but a round or two of cleaning in your dishwasher will wear them down significantly. Whether it's wooden spoons or your knowledge of how to care for your wooden cutting board, skip adding them to the next cycle.

Karina Toner, professional cleaner and operations manager at Spekless, says, "Wood absorbs water and is sensitive to heat, so prolonged exposure in the dishwasher can cause wooden items to crack, warp, or split."

Bacteria and debris can work their way into these cracks as well, making these kitchen tools unhygienic to work with. Instead, wash your wooden kitchenware by hand using mild dish soap like the plant-based seventh-generation clear liquid dish soap from Walmart and water, then thoroughly dry before storing.

"For deeper cleaning and a nice-smelling kitchen, you can scrub your wooden items with a paste of baking soda and water mixed together," adds Karina. Baking soda is available at most stores if it's not already in your pantry.

2. Non-stick or cast iron cookware

Even though your non-stick cookware will likely accumulate less grime than other items in your kitchen, I understand the temptation to put them in with the rest of your dishwasher cycle. However, doing this can ruin your pan's coatings and make them prone to becoming dirtier in the future.

Muffetta Krueger, owner of Muffetta's Housekeeping, says, "Over time as you run your non-stick items through the dishwasher the high heat and harsh detergents used for cleaning will degrade the non-stick coating. It'll peel or chip away, and no longer be non-stick."

The same issue can happen to cast iron cookware, as dishwashers strip away their protective sealant. The water from your dishwasher can then cause cast iron to rust. To keep your coatings intact, wash your non-stick and cast iron pans and pots with a soft sponge and warm, soapy water. "I recommend avoiding using abrasive scrubbers as they can ruin non-stick coatings, but rubbing coarse salt onto hard-to-clean residue can help," adds Muffetta.

The scotch-brite zero-scratch scrub sponges from Target are a popular choice for cleaning these items safely.

3. Insulated mugs and bottles

Similarly to non-stick products, your insulated mugs, bottles, and flasks won't fare well if they're passed through the dishwasher. The very magic that allows them to keep your drinks ice cold or warm for hours relies on a special seal that's delicate — too delicate to survive being washed by a machine.

"There is a vacuum seal between the walls of insulated mugs and bottles, and this can be compromised by the heat of a dishwasher,' says Karina. 'If this seal breaks, the loss of insulation effectiveness will cause your mug to be unable to regulate the temperature of drinks anymore."

Simply wash your insulated goods using warm soapy water, then thoroughly dry them before storing them. It's recommended to keep any lids off of your bottles overnight to ensure no moisture gets trapped inside the bottle that could encourage rust or mold and to regularly clean your bottles using a bottle brush to reach all areas inside.

The munchkin sponge bottle brush from Target is gentle and flexible, able to wash all the little nooks in your bottles without causing scratches.

4. Knives with high quality blades

Your specialist kitchen knives require specialist levels of care, which don't include washing them in a dishwasher. "Knives can lose their sharpness and may become misaligned or corroded if they are washed in a dishwasher," says Muffetta. "Detergents dull blades and high water pressure can damage handles, especially if they are made of wood or plastic."

These knives should be hand washed as soon as possible after use so food doesn't stick, then dried thoroughly. "Drying your knives well is important to prevent rust," says Muffetta.

The HENCKELS classic razor-sharp 8-inch slicing knife from Amazon is the website's top-rated product, German-engineered by a company that has been creating kitchenware for over a century. To sharpen your knife, we recommend using a tumbler like this rolling knife sharpener from Amazon.

5. Crystal glassware and delicate items

If you have a lovely set of crystal glassware or hand-painted ceramics, washing them by hand with a soft sponge or cloth is far safer than running them through a dishwasher for several reasons. "Crystal is delicate and can become etched or chipped from the high heat and abrasive detergents used in dishwashers," says Karina.

The same thing can be said for decorated items: "The high heat and abrasive detergents used in dishwashing can chip, fade, or peel decorative finishes," adds Muffetta.

Your glasses may come out cloudy and need washing again anyway, so you save yourself time by washing them manually to begin with. Hand washing is also the best way to ensure that unique, potentially irreplaceable painted ceramics are preserved as well as possible.

6. Soft plastics or disposable containers

It's important to reuse disposable containers, but washing them in temperatures that are too high will cause them to warp and even harm your dishwasher. "Lightweight plastics can warp or melt under high temperatures, releasing harmful chemicals into our dishwasher and onto the rest of our dishes," says Muffetta. "These chemicals can then go on to contaminate any food stored inside the containers later on."

Warm, soapy water is the solution to cleaning your food storage containers, as it is with many products that aren't dishwasher safe. "Always check for a dishwasher-safe symbol before attempting a machine wash," adds Muffetta.

FAQs

How do you know if an item is dishwasher safe?

Muffetta Krueger, owner of Muffetta's Housekeeping, says, "While dishwashers are a convenient tool in the kitchen, not all items are built to withstand their high heat, water pressure, and abrasive detergents. By learning which items are not dishwasher safe and how to clean them properly, you can protect your cookware, utensils, and cherished kitchen tools."

Muffetta shares the following four tips to discern whether an item is good to go into your dishwasher:

1. Check for a Symbol: Look for the dishwasher-safe symbol, often found on the bottom or packaging of the item. This symbol can vary depending on the item, so do some research.
2. Material Matters: Common dishwasher-safe materials include stainless steel, tempered glass, and certain types of hard plastic.
3. Manufacturer Guidelines: When in doubt, consult the manufacturer’s care instructions for your item.
4. Avoid Risky Materials: Assume wooden, brass, delicate, or adhesive-based items are not dishwasher safe unless explicitly stated.