22 Things You Should Never Put In The Dishwasher

Avoid a dishwasher disaster.

A dishwasher can work some serious wonders in the kitchen and be a real timesaver. It's a magical machine that replaces a precarious pile of dirty dishes with squeaky clean plates. Every holiday, tailgate, and bake sale season works overtime yet still delivers. You love the ease and convenience of using your dishwasher until that moment when you find your favorite coffee mug or keepsake plate broken.

It's a devasting mistake, but it happens to every avid dishwasher user. There's a way to avoid these mistakes, but it might require some elbow grease and a return to hand-washing dishes. Here's a list of things you should never put in the dishwasher.

Things You Should Never Put In Your Dishwasher
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To Prevent Dull Edges

Chef's Knives

A sharp chef's knife can make or break your dinner prep, and putting it in the dishwasher dulls the blade over time. Instead of throwing your best tools into the machine, wash chef's knives by hand to keep them in tip-top shape.

Food Graters

Like your best chef's knife, you wouldn't want the dishwasher to dull the blades in a food grater. This kitchen tool is best cleaned by hand.

To Prevent Fading

Copper Mugs & Cookware

Copper is a classic yet stylish pick for your cookware, and copper mugs are perfect for serving Moscow Mules year-round. After a big holiday party, throwing a copper mug into the dishwasher is tempting, but this drinkware will not sustain many cycles through the dishwasher. Make sure to hand-wash any copper items or other precious metals to keep their shine and luster intact and avoid discoloration or tarnishing.

Milk Glass

Whether you're collecting vintage milk glass bowls from your great aunt or retro-inspired glassware from Anthropologie, be sure to hand-wash them unless you're ready to risk discoloration. The semi-opaque milk glass will look yellow after a cycle through the dishwasher.

Drinkware, Measuring Cups, or Plates with Text

Over time, items with text can fade after many cycles in the dishwasher. A measuring cup isn't helpful when the lines have disappeared.

Melamine Dishes

Melamine dishes and serve ware have withstood the test of time and proven popular even with the invention of new materials. Vintage melamine dishes and reproductions often have patterns or designs, so colors can crack or dull in a dishwasher.

Metallic Gold Flatware

Unlike its silver counterparts, the sheen on gold flatware fades over time when using a dishwasher. This fading also goes for plates with a gold-metallic design, so to be safe, always hand-wash these items.

Hand-Painted Items

Your favorite hand-painted decorated piece won't look the same once it starts to fade. To protect decorative or delicate plates, mugs, or any other painted items, hand-wash and gently scrub with a smooth sponge, so you don't peel off any paint.

Paper Items

These will fade in the dishwasher if a mug has any decorative paper elements. Similar to text and other decorative embellishments, paper is too delicate to withstand the heat and hot air in a dishwasher.

To Prevent Structural Damage

Insulated Mugs & Cups

Your favorite and most trusted travel mug might not be airtight after a couple of visits to the dishwasher. The same goes for plastic or metal insulated cups. The insulated airspace that keeps your hot or cold liquids gets compromised and loses efficiency. If you're desperate because you finally found a lost insulated tumbler under your car seat after a long, hot summer month, opt for the top rack and skip the high heat of the drying cycle.

Eggs for Baking Prep
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Wooden Utensils & Cutting Boards

The dishwasher's hot water and dry heat can warp or crack wooden kitchen utensils and cutting boards, rendering them less-than-useful. The heat dries natural wood cutting boards, making them look sad and faded.

Pressure Cooker Lids

This one is a big no-no. While your pressure cooker pot might be acceptable, the lid poses a safety issue. The dishwasher cycle can warp or damage the rubber seal on the cover, as well as damage the valves and vents that the lid uses when cooking. These things can lead to many problems, including pressure cooker explosions.

Nonstick Skillets & Sheet Pans

Some nonstick cookware reportedly is "dishwasher safe." We don't distrust that fact, but we also know that the dishwasher can degrade the nonstick coating on your nonstick skillets and sheet pans, rendering them less effective. Read your labels, and proceed with caution.

To Protect Materials

Aluminum Cookware

The dishwater's scalding water can stain or dull aluminum cookware. Stainless steel has a better chance in the machine, but you should always check the labels after purchasing. In our experience, better safe than sorry!

Cast-Iron Skillets

Your cast-iron skillet is such a game-changer for gooey cobblers and classic cornbread that it'd be a real shame to lose it. The seasoning on a cast-iron skillet makes it unique, and the dishwasher can degrade the coating and eventually lead to rust.

Fine China

This rule should be a given, but we'd never get past the guilt if we didn't at least give fair warning. Before you line up your heirloom dishes in the dishwasher, think again. It can cause them to chip, fade, or lose their finish. This practice is essential if the patterns have metallic detail.


Crystal stemware and dishes can crack, chip, or break due to the high heat of a dishwasher. These pieces can also be stripped of their sheen or become etched or cloudy after repeated washings. Check the manufacturer’s directions before loading because some types cannot be washed even on a dishwasher’s delicate cycle, or play it safe and hand-wash.

How To Clean Dishwasher Filter
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As previously mentioned, with metallic gold items, a pewter serving dish will not withstand many cycles through the dishwasher. As many pewter items are vintage or antique, this is especially true because of the delicate construction.


Unless specifically designated as "dishwasher safe," placing a plastic container in a dishwasher runs the risk of melting at extreme water and air temperatures. Even if technically "dishwasher safe," a plastic container continuously placed in a dishwasher risks losing its sturdiness over time which can be dangerous if pieces of the plastic end up in your food.

To Protect the Dishwasher

Plates with Food On It

This decision is a highly debated topic regarding dishwashers, but placing dishes with large pieces of food on them will not do your machine any good in the long run. Leaving food on a plate can clog your dishwasher, making it susceptible to breaking in the future.

Broken Dishes

If a plate or mug already has a chip in it, that dish is more likely to continue cracking when put through the dishwasher cycle's hot water and dry heat. Not only is this not a good practice for your dishwasher, but it can also potentially be harmful as pieces can fall apart during your subsequent use.

Containers with Adhesive Labels

The first stop is always the sink or dishwasher to save glass jars and containers for reusable storage. However, it's crucial to remove the paper label beforehand. If a piece dislodges during the cycle, it can clog the dishwasher drain and food disposal system and lead to damage with a hefty price tag.

So always remember, your dishwasher works some magic, but not miracles. Keep this list handy, and don't ruin your favorite kitchen tools.

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