A dishwasher can save time and effort, but not everything in your kitchen belongs inside it. High temperatures, strong detergents, and powerful water jets can damage certain materials. Before loading an item, check the manufacturer’s instructions, especially if it is marked “hand wash only.”

Sharp knives are best cleaned by hand because repeated dishwasher cycles can dull their blades, especially when they knock against other utensils. Wooden spoons, cutting boards, and handles can also suffer from prolonged exposure to heat and water, which may cause them to crack, warp, or fade. Wash wooden items gently and dry them immediately.

Delicate crystal glasses, fine china, and decorative dishes also require extra care. Dishwasher cycles can cause crystal and porcelain to chip, crack, become cloudy, or lose decorative finishes. Cast iron should also stay out of the dishwasher because detergent can strip away its protective seasoning, leaving the cookware vulnerable to rust.

Nonstick cookware is another item worth washing by hand. Repeated dishwasher exposure can gradually wear down some nonstick coatings. A soft sponge, mild dish soap, and gentle cleaning can help preserve the surface. Allowing a hot pan to cool before washing can also help prevent sudden temperature changes that may cause warping.

Finally, be cautious with containers that have adhesive labels and insulated travel mugs or thermoses. Heat and water can loosen labels, creating sticky residue that may cause problems inside the dishwasher. Some insulated containers can also have their vacuum seals damaged by excessive heat. A little extra hand washing can help protect your favorite kitchen items and extend their useful life.