15 Things You Should Never Put In the Dishwasher

Your trusty wooden stirring spoons — and any wood or wood-handled utensils for that matter — can warp and crack in the heat of the dishwasher. It’s important to hand wash these items with a mild detergent, dry them with a towel and then let them fully air dry. Also, avoid letting them sit in the bottom of your sink. Soaked wood utensils absorb too much moisture, which can also lead to damage.

When it comes to things you shouldn't put in the dishwasher, this one is definitely at the top of the list. Seasoned cast iron pans don’t need much in the way of cleaning. In fact, a simple wipe-down after use is usually enough to keep these products working for generations. Dishwashing detergent is too harsh for the seasoned finish and can even result in rust. When you do need to clean your cast iron, use a stiff brush and hot water, then re-season on the stove with a layer of oil.

The dishwasher can affect the vacuum seal on insulated mugs and popular water bottles. Once it’s broken, your vessel won’t keep your beverage hot or ice cold for as long as the product is advertised. Don’t spend a lot of money on a nice mug if you’re not going to hand wash it! It only leads to disappointment and frustration and can void your warranty.

Crystal glass is delicate and can easily become etched, scratched and made cloudy by the heat and detergent in the dishwasher. Instead, plan to hand wash these delicate pieces with dish soap and warm water. To reduce water spots, dry by hand with an absorbent dish towel.

Heat and water pressure inside the dishwasher can damage the nonstick coating on your pots and pans, and yes, that includes ceramic cookware. Not only will you extend the life of the cooking surface by hand washing these items with a soft sponge in the sink, but you’ll save a lot of space in the dishwasher, too.

We love a Moscow mule, but after happy hour, it’s important to keep those cups out of the dishwasher. The dishwasher can dull the desirable coppery shine and cause unwanted discoloration. The same goes for any copper pots and pans in your collection; it’s always best to hand wash and dry these items to protect the finish. Already experiencing some tarnish or dulling? Add some baking soda to a damp cloth and rub the surface gently to polish the copper.

Gold-plating used on flatware is more delicate than ordinary stainless steel. The dishwasher can tarnish and, even worse, wear away the gold plating. Make it a point to hand wash these utensils instead so the delicate finish lasts longer.

The small holes in your cheese grater and fruit zester aren’t easily cleaned in the dishwasher. While the water pressure can clean the surface, you’ll probably notice that food and rinds will remain trapped in the tiny blades. Also, the curved edges of a box grater can rust over time because the construction retains penetrated water. Instead, we highly recommend that you wash surfaces by hand using a stiff-bristled brush to clean food out of the blades.

Pressure cooker lids shouldn't go in the dishwasher because the detergent and heat can damage the seals and valves. Not only will a faulty seal affect performance and the overall functionality of the appliance, but it also puts the user at risk for steam burns and other unexpected failures. To clean your lid, just use dish soap and water, then allow it to air dry completely before reassembling the cooker.

You’ll regret putting any of your vintage china into the dishwasher, even on a delicate cycle. Ask me how I know! The delicate patterns and glazes are easily destroyed by the heat and water pressure. Instead, treat these pieces as highly fragile items and hand wash them carefully in the sink. (Curious if antique milk glass is any more durable for the dishwasher? It’s not. The heat can actually cause it to become brittle and discolored.)

Dishwashers and sharp kitchen knives don’t mix! Not only can high heat and strong detergent weaken the metal and corrode (or even rust) metal knives, but the elements also affect knife handles. Additionally, the physical jostling that a knife endures during the wash cycle causes the blades to bump into other silverware, which dulls the blades and can cause nicks. Hand washing and drying is always recommended for kitchen knives.

Adhesive and heat don’t mix. If you need to wash an item that’s been repaired (whether by tape or super glue) it’s always best to opt for hand washing. Did you fix a serving dish? Hand wash it. Glue your favorite coffee cup together? Hand wash. Also, do you put stickers on your water bottles? The heat and pressure from the dishwasher will definitely affect the adhesive around the sticker edges and degrade its quality over time.

Plastic containers shouldn't go in the dishwasher — the high temperatures can cause warping and chemical leaching. Not only that, but transparent plastic is more likely to get cloudy. Plus, it can become brittle after repeated heat exposure. Glass containers are a better solution, but even the plastic lids of your favorite storage containers should be hand washed to extend their lifespan.

The dishwasher can cause a soapy residue to build up on your silicone mats, but you can avoid that by hand washing your sheets in the sink. Silicone reusable “plastic bags” are in the same boat. Flip the material inside out and give it a good wipe-down between uses to remove food particles and oils that can cling to the surface.