The dishwasher is one of the most frequently used appliances in any home. It’s not just for washing utensils; it’s handy for a variety of items you might not realize can go inside. In this article, it’s noted that scourers, brushes, bathroom and kitchen accessories, or plastic toys can sometimes be cleaned in the dishwasher. But there are also several items that should never go in the dishwasher, and this piece explains why.
Because a dishwasher works at high temperatures, certain objects can be damaged or their lifespan shortened by the heat and detergents. The Consumer and User Organization OCUs guidance emphasizes watching for the terms dishwasher safe or dishwasher-friendly on dishes and flatware. Those labels are meant to protect delicate items and ensure effective, gentle cleaning without harming materials.
Here is a guide to items that should not be placed in a dishwasher.
Sensitive glass and crystalware
Crystal glasses deserve extra care. Their delicate nature means heat and aggressive detergents can dull their sparkle and reduce clarity. If items are especially fragile, porcelain, or hand-painted, it’s wiser to wash by hand to preserve their shine and finish. If one still chooses to run them through a cycle, select a low-temperature setting and secure each piece so it cannot rattle during washing. Such precautions help keep the glassware’s appearance vibrant and intact.
Wooden-handled knives
Knives with wooden handles or those with hardware that is not stainless can suffer from dishwasher exposure. Detergents and the high heat can cause wooden handles to swell or crack and can accelerate rusting on metal parts. It is generally best to wash these knives by hand, drying them promptly and storing them safely.
Wooden kitchen utensils
Wooden spoons, cutting boards, and other wooden kitchen tools should not be cleaned in a dishwasher. Prolonged exposure to heat and moisture can cause warping, cracking, or splitting. Hand washing with a mild detergent, followed by thorough drying, helps preserve their shape and effectiveness over time.
Non-stick cookware
Non-stick coatings, including Teflon and similar surfaces, are best cared for with gentle washing by hand. The heat and harsh detergents can wear away the coating, which may lead to food sticking or flaking. When in doubt, always follow the manufacturer’s care instructions, but hand washing is a reliable rule of thumb for longevity.
Pressure cooker lids
The valves and seals on pressure cooker lids can trap debris. If washed in a dishwasher, residues can accumulate and the rubber gaskets may lose elasticity faster, reducing the seal and effectiveness. Cleaning these parts by hand with attention to the valve paths helps maintain proper performance.
Iron cookware
Bowls, pots, and kettles made of iron can lose their seasoning or protective coatings when exposed to dishwasher cycles. Regular dishwashing can strip away protective surfaces and lead to rust or dull finishes. Hand washing and careful drying is typically the safer approach for iron items.
Untreated copper and unpolished aluminum
High temperatures and aggressive detergents can cause discoloration, spotting, or dulling on untreated copper and aluminum utensils. These metals may also react with standard dishwasher detergents, altering their appearance over time. Cleaning these items by hand is usually the better option to maintain their natural luster.
Jars with paper labels
Papers attached to jars should not be put through the dishwasher because fragments can detach and clog the dishwasher drain or create other blockages. Removing labels before washing helps protect the appliance and keeps drainage smooth.
Plastic plates and cups with printed designs
Plastic dishware with printed graphics should only go into the dishwasher if the manufacturer confirms it is safe for dishwashers. Repeated heat exposure can cause colors to fade or the plastic to warp, especially on lower-quality pieces. When in doubt, wash these items by hand to preserve images and shapes.