Can metal go in the dishwasher? Guidance for renters using older apartment dishwashers

Short answer

Why people ask this

Renters with older apartment dishwashers worry that the machine is rougher on metal items than newer models. These units may lack sensors, run hotter, and have worn racks or missing tine caps from previous tenants. Property-supplied appliances also come with lease rules and potential deposit risks if items discolor the tub or rust spreads. Hard water in some buildings and older heated-dry cycles can accelerate pitting, blackening, and knife dulling.

When it might be safe

• Stainless steel flatware and cookware clearly labeled “dishwasher safe,” especially if placed on the top rack and with heated dry off
• Enameled steel or enamel-on-steel pieces with fully intact enamel and no chips exposing bare metal
• Anodized aluminum specifically marked dishwasher safe by the manufacturer (older machines: use gentle/eco cycle and air-dry)
• Stainless steel travel mugs or bottles without insulation and without painted/printed exteriors

When it is not safe

• Bare (uncoated) aluminum pans or utensils, which can blacken and pit in older, hotter cycles
• Cast iron, carbon steel, and blue steel (seasoning will strip; rust risk is high)
• Copper or brass items, and gold- or black-oxide–finished flatware (tarnish, discoloration, and finish loss)
• Fine knives (especially high-carbon steel or thin-edged chef’s knives) that dull and spot quickly
• Aluminum pans with nonstick coatings not rated for dishwashers (coating can degrade faster in older units)

Possible risks

• Pitting and blackening from harsher detergents plus older heated-dry elements running hot
• Rust transfer from chipped rack tines common in older apartment machines
• Dulling and micro-chipping of knife edges due to longer, hotter cycles and rattling spray patterns
• Discoloration or tarnish on copper/brass that may stain the tub, risking lease or deposit issues
• Galvanic corrosion when mixed metals touch during the cycle, especially with hard water in older buildings

Safer alternatives

• Hand-wash high-risk metals (cast iron, carbon steel, bare aluminum, copper, fine knives) to avoid deposit or damage disputes
• If you must machine-wash, use top rack, a gentle/eco cycle, and turn off heated dry; open the door to air-dry
• Test one inexpensive stainless item first on a short cycle to see how your specific machine and water behave
• Use a silicone rack cap kit to cover any exposed metal tines and reduce rust transfer in older racks
• Keep unlike metals from touching, and secure knives in a basket or sheath to prevent edge damage
• Check the lease or building policies and the appliance manual; follow manufacturer labels over generic advice

Bottom line

In an older apartment dishwasher, many stainless items labeled dishwasher safe will be fine, but bare aluminum, cast iron, carbon steel, copper/brass, and fine knives are risky. Because older units often run hotter and have worn racks, use gentle settings, air-dry, and test with a low-value item first. When unsure, hand-wash to avoid damage and potential lease or deposit issues.

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