While your dishwasher is certainly a bit help in the fight to keep your kitchen clean, it can’t handle everything—some things just shouldn’t go in dishwashers. Particular items can be damaged during a cycle, or worse still, can damage the dishwasher itself!

Cast your eye over this list and remember to keep these items well away from your appliance.

Sharp chef’s and kitchen knives

Not only will the washing process cause damage to high-quality blades and their handles, but sharp knives can nick the plastic coating around the racks, which can in turn lead to rust. It’s definitely best to wash these by hand to keep blades sharp and your appliance at its best.

Wooden utensils and bowls

Dishwasher detergent can wash away the natural oils in wood which prevent the material from drying out. If this happens, your utensils and bowls are liable to crack and warp. Wash these by hand with mild detergent and warm water, and don’t leave them to soak.

Cast iron cookware

Cast iron skillets and pans are some of the best cookware available, especially once seasoned with oil to create the perfect cooking surface. The heat and detergent in a dishwasher will strip you cast iron cookware of this seasoning, leaving it unusable. Elbow grease is best for cleaning these items, but just be sure to thoroughly dry them to avoid rusting.

Non-stick pans

Despite being labelled as dishwasher safe, the heat and detergent in dishwashers can wear away the non-stick coating over time. If you do need to put these in the dishwasher, skip the drying process, as this is where most of the damage is caused. Remember, if you see any scratches or flaking on the pan surface, throw it away—toxins can be released from under the non-stick surface.

Copper pans

Copper has a bright, vibrant shine and looks beautiful. The chemicals in dishwasher detergent will take this shine right off, and even worse, may cause pitting. No amount of copper polish will fix that!

Aluminum cookware 

Aluminum cookware looks great with its bright, shiny surfaces. The harshness of dishwasher detergent will take that shine right off, and chemical reaction may cause spots to form on the surfaces too. Handwash these items to keep them looking their best, even if they claim to be dishwasher safe.

Insulated containers

Insulated containers and thermoses are great for keeping things hot or cold, but unless they’re labelled as dishwasher safe they certainly shouldn’t find their way into your dishwasher. The heat in the appliance can break the seals which give these items their insulating properties.

Printed or painted glassware

Whether it’s a measuring jug or decorated pint glass, repeated cycles in the dishwasher will wear away anything printed or painted on glassware.

Vintage china, porcelain, crystal and other delicate items

If you’ve shelled out the money for something with a bit of heritage, it’s best to keep these items out of the dishwasher. Detergent and heat can cause damage to decoration, and even with the best will in the world, more delicate items are liable to chipping if they hit up against others during a cycle. 

Thin plastic containers

While many food containers are dishwasher safe, things like take-away boxes, butter tubs and thin plastic container boxes won’t be able to stand up to the heat of the dishwasher and will warp.