6 Things You Should Never Put in the Dishwasher

The dishwasher is one of the most convenient appliances in the home. After a big dinner party or an involved cooking session, it's a huge relief to be able to throw everything in the dishwasher and call it a night. (It can even save you money to run a load right before you go to bed.) But, not everything should go in the dishwasher. Some items can end up getting damaged or ruined when put through a dishwasher cycle—and other items can ruin the machine itself. So, here’s what you should never put in the dishwasher to keep both your favorite dishes and your appliance in good shape.

Cast Iron Pans

Cast iron is wonderful for cooking but not such a favorite for cleaning. Brian Jones, ASKO Product Expert and VP of Marketing tells me this material needs to be washed by hand. “These unique pans lose their nonstick surface in the dishwasher and become susceptible to rust," he says.

Nonstick Pans

Jones adds that nonstick pans should be hand-washed as well. While some non-stick pots and pans are touted as dishwasher-safe, hot water can still wear away the surface prematurely. If you are going to put them in the dishwasher, it’s best to wash these on the top rack. Just know they might not last as long as they would if you only washed them by hand. Or, limit machine washing these pans to only every once in a while, such as after a dinner party or on those nights when you are too exhausted to clean.

Special Knives

Jones also notes that certain knives, such as steak knives, chef's knives, and paring knives, should not be put in the dishwasher, because it dulls them and shortens their lifespan. However, you’re probably fine throwing the average butter knife in the dishwasher.

Wooden Items

Anything made from wood should also be kept out of the dishwasher. “Wooden spoons and cutting boards can warp and crack in the dishwasher due to the prolonged moisture exposure and the high heat,” Jones explains.

Fine China

Lastly, fine china (especially if it’s vintage) and some melamine dishes should not be washed in the dishwasher. If you aren't sure if a particular dish can be machine washed, it's probably better to play it safe and just wash it by hand.

Items That Can Damage Dishwashers

Damaging your dishwasher can be an incredibly frustrating and costly mistake. So, Jones suggests keeping this rule in mind: If it isn’t a dish or something you cook in, it probably shouldn’t go in the dishwasher. “Some people put items like car parts and garden tools [in the dishwasher], which you should never do," Jones says. "Other less obvious items that can damage your dishwasher include jars with paper labels—because the glue can melt and clog the filter—as well as some plastic containers, since small pieces can break off at high temperatures and damage the filter,” he explains.

However, unless otherwise noted on the item itself, plastic dishware or cutting boards can usually be cleaned in the dishwasher safely. But it’s best to put them in the top rack or use a low or no heat setting to keep them from melting or warping.