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15 Things You Should Never Put In The Dishwasher

15 Things You Should Never Put In The Dishwasher

Although automatic dishwashers are no short of a scientific wonder that offer convenience and efficiency in keeping our dishes sparkling clean, not everything that fits in the dishwasher should be placed.

However, knowing the items to avoid washing in the dishwasher can save you the money you might spend on repairs or replacement later. For example, only certain pots and pans can be washed in the dishwasher. 

While this appliance can handle many items, we’ll cover the 15 things you should never put in the dishwasher. It is to help you protect delicate items, preserve cookware's performance, and ensure longevity.

Before we move onto the list of things you shouldn’t put in the dishwasher, here is a quick reminder that using a reliable, effective, and trusted dishwasher detergent is equally important to ensure optimized cleaning results. 

1. Wooden utensils (spoons, bowls, and cutting boards)

Anyone who has ever owned a dishwasher must have at least asked themselves, “can wood go into the dishwasher?” As tempting as it sounds, it’s probably not the best idea. A harsh dishwasher detergent can strip natural oils that prevent wooden utensils from drying and cracking. 

Hand wash wooden utensils carefully with mild detergent and warm water, avoiding soaking to prevent swelling and distortion.

2. Kitchen knives

Kitchen knives are not dishwasher safe items. Their edges can nick the protective coating on the racks and baskets, which can cause rusting. Knives are also dangerous when loading onto and unloading from the dishwashers. 

In addition, knives should be washed by hand in a sink, as harsh dishwasher detergent can dull edges and damage wooden handles.

3. Graters and sieves

Just like kitchen knives, graters, and sieves can also nick the plastic coating on the racks that protects them from rust. 

For optimal results, hand wash items with small holes instead of crowding them into the dishwasher, as the water stream may struggle to remove all food particles.

4. Cast iron cookware

Dishwashing cast iron cookware with harsh detergents and excessive water removes the protective oil layer, making it susceptible to rust and unusable.

Avoid using the dishwasher to clean cast iron cookware covered in black crud, as tempting as it may be. Opt for traditional elbow grease instead.

5. Aluminum cookware

Avoid putting shiny disposable aluminum plates, pots, pans, and baking sheets in the dishwasher. Harsh dishwasher detergents can cause them to turn dull, darken, pit, and corrode. Even if labeled "dishwasher safe," it's best to hand wash. 

Worried about the cleaning operation for your cookie sheet, muffin tin, and glass baking dish? - Here's how to clean baking pans/sheets in your dishwasher

6. Ceramic pans and cookware

Ceramic pans and cookware aren’t entirely made of ceramic. Instead, they only have a ceramic coating bonded to the metal of the cookware. 

Washing ceramic items in the dishwasher isn’t recommended, as the detergent chemicals might be too harsh for the ceramic finish. 

7. Acrylic or melamine dishes

Lightweight and non-breakable acrylic or melamine dishes can acquire damage from excessive water, harsh dishwasher detergent, and drying temperatures of the dishwasher. 

Cheaper sets, in particular, may develop hairline cracks and experience color and design loss after multiple washes. Preserve their longevity by hand washing them.

Don’t forget to read our dishwasher temperature guideline article to know the right temperatures required for the most optimal cleaning performance.   

8. Insulated glasses, tumblers, and thermal containers

Plastic and metal insulated cups, tumblers, and containers are constructed with two layers of material with airspace - responsible for the insulation between the two. 

While some containers are labeled as dishwasher safe, many are not. Therefore, hand-washing both plastic and metal insulated containers is best. 

If you decide to place one in the dishwasher, opt for the top rack and skip the high heat of the drying cycle that can cause the seal to break and water to enter the airspace.

9. Glassware (printed or hand painted)

Harsh detergent and water spray can remove the paint or print from the glassware in just one or two washes. Also, even if heat-fired, hand-painted glassware should never be placed in the dishwasher.

10. Thin plastic containers

Placing thin plastic containers in the dishwasher may cause them to melt or warp due to high heat. To minimize this risk, use the top rack and avoid the high-heat drying cycle. Instead, remove them from the dishwasher and allow them to air dry.

11. Vintage china, delicate crystal, and repaired items

It is better to hand wash any vintage glass or china heirloom, especially if they have been repaired, as dishwasher’s wash can weaken adhesives and potentially cause the loss of small pieces.

Hand wash delicate crystal to prevent chipping. Place glasses between tines on the top rack in the dishwasher, avoiding breakage. Note that harsh detergents can etch lead crystal, causing cloudiness.

12. Milk glass

Vintage milk glass dishware, including milk glass, may turn yellow when repeatedly washed in the dishwasher. Preserve their appearance by hand washing these pieces.

13. Pressure cooker lid

Never wash pressure cooker lids in the dishwasher, as small food particles or dishwasher detergent can collect or lodge in the regulator or safety valves. Instead, wash pressure cooker tops, gaskets, and pots by hand in warm, soapy water. Rinse and dry well. 

14. Anything with paper labels

Avoid putting anything with paper labels in the dishwasher as it can loosen or remove them. However, if you must wash them in the dishwasher, remember to remove the paper labels from bottles or jars to prevent clogging the dishwasher drain, filter, and food disposal system.

Read our article about cleaning and unclogging the dishwasher filter to ensure the appliance performs optimally. 

15. Nonstick pots and pans

Unless explicitly labeled as dishwasher safe by the manufacturer, it is recommended not to place cookware with a nonstick coating in the dishwasher. 

This is because dishwashing can degrade the coating over time, leading to flaking during cooking and compromising the nonstick finish.

So there you have it, the 15 things you should never put in the dishwasher to safeguard, maintain, and enhance their performance and durability.