Introduction
Dishwashers are one of the greatest time-savers in modern kitchens, making clean-up fast and effortless. But not everything belongs inside. Some items can crack, warp, rust, or lose their quality after just one wash cycle. Knowing what not to put in the dishwasher can save you money, preserve your favorite kitchen tools, and avoid unnecessary frustration.
In this guide, we’ll cover 6 things you should never put in the dishwasher — with clear explanations, safer alternatives, and expert resources. For a complete list of dishwasher-safe and unsafe items, check out Whirlpool’s detailed guide.
1. Cast Iron Pans
Cast iron is durable, but it doesn’t belong in the dishwasher. The harsh detergent and high heat strip away the protective seasoning layer, leaving the surface prone to rust.
Safer Alternative: Hand-wash with hot water and a stiff brush. Dry thoroughly and lightly oil the surface to maintain seasoning.
👉 Related query answered: Can you put cast iron in the dishwasher? — No, always wash by hand.
2. Wooden Cutting Boards and Utensils
Wood absorbs water, and dishwasher heat causes warping, splitting, and cracking. Plus, the detergent can dry out the natural oils in wood.
Safer Alternative: Wash quickly with warm soapy water, rinse, and air-dry upright. Apply food-grade mineral oil occasionally to keep wood from drying out.
👉 Related query answered: Is it safe to put wood cutting boards in the dishwasher? — Absolutely not.
3. Sharp Knives
Dishwashers dull blades quickly. The powerful jets knock knives around, damaging edges and even chipping the blade. Handles may also loosen over time.
Safer Alternative: Wash knives carefully by hand and dry immediately. Store them in a knife block or magnetic strip.
👉 Related query answered: Why should you not wash sharp knives in the dishwasher? — It ruins both the blade and handle.
4. Fine China and Crystal
Delicate dishes, heirloom china, and crystal glasses are too fragile for the dishwasher. Heat and vibration can cause cracks, and detergent can dull the finish.
Safer Alternative: Hand-wash with a soft sponge, mild soap, and warm water. Line the sink with a towel to prevent accidental chips.
5. Nonstick Cookware
Many nonstick pans aren’t truly “dishwasher safe.” Repeated cycles break down the nonstick coating, leading to flaking and reduced lifespan.
Safer Alternative: Wash with a soft sponge, warm water, and gentle dish soap. Avoid abrasive scrubbers to protect the coating.
6. Copper and Aluminum Cookware
These metals react poorly to dishwasher detergent. Copper tarnishes and loses shine, while aluminum can oxidize, discolor, or pit.
Safer Alternative: Hand-wash with mild detergent and dry immediately. For copper, polish with a specialized cleaner to maintain its glow.
Frequently Asked Questions
Can you put stainless steel in the dishwasher?
Yes, most stainless steel is safe, but knives, insulated mugs, and some delicate items should still be hand-washed.
Are plastic containers safe in the dishwasher?
Some are, but always check labels. High heat can warp thin plastic or release chemicals if not BPA-free.
What happens if I accidentally put a “dishwasher-unsafe” item inside?
One cycle may not destroy it, but repeated washes will cause lasting damage. Hand-wash immediately afterward to minimize harm.
Conclusion
Dishwashers make life easier, but they’re not a one-size-fits-all cleaning solution. Knowing what not to put in the dishwasher — from cast iron pans to delicate crystal — helps you extend the life of your kitchen tools and avoid costly replacements.
When in doubt, stick to hand-washing. It takes a little more time but saves you from big headaches later.
👉 You might also enjoy: Things to Look for When Buying a Dishwasher