That headline is partly useful, but often exaggerated. Dishwashers are convenient, yet some materials really do get damaged by heat, strong detergent, and water pressure.
Here are 8 things you generally should NOT put in a dishwasher—and why:
🪵 1. Wooden utensils & cutting boards
- Wood absorbs water → warping, cracking, splitting
- Heat dries it unevenly
🔪 2. Sharp kitchen knives
- Dishwasher dulls blades
- Can knock against other items and chip
🍳 3. Non-stick pans
- High heat + detergent damages coating
- Leads to loss of non-stick surface over time
🍷 4. Crystal or delicate glassware
- Can become cloudy or etched
- Risk of cracking or chipping
🍳 5. Cast iron cookware
- Removes protective seasoning layer
- Leads to rust
☕ 6. Insulated travel mugs
- Damages vacuum insulation
- Reduces ability to keep drinks hot/cold
🧴 7. Thin plastic containers
- Can warp or melt
- Especially low-quality plastics
🎨 8. Hand-painted or decorative items
- Designs fade or peel
- Decorative glaze can degrade
🧠 Bottom line
Dishwashers are safe for most modern items, but:
Heat + strong detergent + movement = damage to certain materials over time.
If you want, I can also give you a quick “dishwasher safe vs not safe” cheat sheet you can keep in your kitchen.
