17mar what not to put in the dishwasher hero
Research report
17 March 2017

What not to put in the dishwasher

Sometimes, you need to roll up your sleeves and wash things by hand.

Dishwashers are an appliance of convenience. However, while it’s tempting to throw in everything from the pots and pans to the glassware and cutlery, there are some items that should only be washed by hand.

1. Silver
Whether sterling or plated, silver should never go in the dishwasher. Silver tarnishes easily, and once stained polishing may not remove it. It isn’t necessarily the dishwasher that’s at fault, the detergent used can also tarnish silver. We recommend always hand-washing silver.

2. Fine china
Depending on the age and condition of your china, putting it in the dishwasher can wear away at the pattern or chip and break it. It’s also best to leave gold-trimmed crockery out of the dishwasher as the trim can be stripped away.

3. Crystal and fine glassware
Sensitive to temperature and detergents, these types of delicate glassware are prone to cracking and etching. If your crystal has turned cloudy, try cleaning it with a lime remover as it may not be etched. However, once etching occurs, it is irreversible.

4. Wooden cooking utensils and chopping boards
Wooden cookware can warp and crack from repeated washes in the dishwasher. Chopping boards are a bit more resilient, but the wood can end up drying out too much and gaps and cracks can form. After washing, make sure wooden utensils and chopping boards are completely dry before putting them away to prevent bacteria growth.

5. Utensils with wood or bone handles
The temperatures and detergent in a dishwasher can weaken glue holding the handle to the utensil, causing it to fall off.

6. Cast-iron cookware
Seasoning is the gradual process of building up a protective non-stick surface on cast-iron cookware. Putting a cast-iron skillet in the dishwasher can strip that seasoning and eventually cause it to rust.

7. Copper pots and pans
While your copper cookware won’t be ruined by putting it in the dishwasher, it can become discoloured and require laborious hand cleaning to restore.

8. Brass
The hot temperature inside a dishwasher can cause a chemical reaction that eats away at the protective layer on brass. This layer prevents oxidation and tarnishing. Once it’s gone, you’ll need to polish the item to replace it.

9. Items with labels on them
The dishwasher might seem like an easy way to remove labels from jars. However, once a label peels off it doesn’t go down the drain. It can stick to unseen places in your dishwasher, especially the filter, and cause headaches later on.

Is the top rack safer?

Some kitchenware and utensils come with instructions saying to wash in the top rack only. This is because the top rack of a dishwasher is typically cooler during a hot wash than the bottom rack due to the placement of the heating element. Regardless of which rack you use, you should avoid placing any of the items mentioned above in your dishwasher.

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