A Guide to Dishwasher Safe Symbols

Mar 24, 2020

https://www.appliancecanada.com/dishwashers Tupperware and other plastic containers are ultra convenient for storing leftovers and packing lunches. Once finished with them, it can be tempting to throw them in the dishwasher alongside your other dishware and cutlery. Be wary, however, as not all plastics and ceramics are dishwasher safe. You will often see a variety of sometimes cryptic symbols gracing the bottom of your containers and dishware, which can oftentimes be hard to read and interpret. Too often, containers and dishware are relegated to the dishwasher only to turn out ruined and unusable. This article will aim to decipher some common symbols found on your plastic containers and dishware, as well as outline a list of kitchenware to never use in a dishwasher to help you make the most of your products and ensure their functionality.


Despite the ubiquity of the dishwasher, there is no universally recognized or approved symbol to indicate that an item is dishwasher safe. Below is a brief list of some of the most common symbols you may see to indicate that your tupperware, dishware or any other product is indeed safe to be washed in your dishwasher:

This first symbol shows a dishwasher rack with two dishes inside the dishwasher as they’re getting washed:

This second symbol features a wine glass covered in water droplets:

The final symbol showcases a single dish sitting within a dishwasher rack, with water droplets falling down upon it:

All of these symbols indicate that the item in question is dishwasher safe, and you can proceed to wash it with peace of mind.


While dishwashers are one of the most convenient appliances, allowing you to tackle large batches of dirty dishes and cutlery, they’re far from a cure-all. There are still many kitchenware items that need a good, old fashioned hand-washing. If a piece of dishware or plastic container doesn’t feature any markings leading you to believe it’s dishwasher safe, it’s best to try looking the item up online on the manufacturer’s website, or to call customer service to inquire into best care practices of that item. It’s important to note that the following items are generally not dishwasher safe:


A cast-iron skillet: when you season a skillet before use and then throw it into the dishwasher, you’re essentially undoing all of your hard work. It’s best to simply let it soak in warm water (sans soap), or rub it with some salt.

Wooden utensils: the hot water and air that a dishwasher uses to wash and dry kitchenware is often too hot for wooden utensils and can cause them to warp.

Wooden cutting boards: much like the wooden spoons and other utensils, throwing a wooden cutting board into a dishwasher will cause it to warp and lose its colour. To clean, try using a mixture of ¾ cup chlorine bleach and one gallon of water.

Vintage plates: vintage china with hand-painted designs and gold trim doesn’t fare well with the hot water and detergents found in dishwashers, as they will often wash these beautiful details away.

Garlic press: given garlic’s sticky nature, it will often get stuck into the small crevices of any garlic press. Wash this by hand to ensure it’s completely clean and ready for its next use.

Insulated mugs: while some newer models of insulated travel mugs may indicate that they’re dishwasher safe, many will lose their insulation when exposed to the high heat and detergent of a dishwasher.

Aluminum kitchenware: any items made out of aluminum run the risk of discolouring when exposed to a dishwasher.

Cheese graters: much the same as a garlic press, cheese graters will often have small remnants of sticky cheese attached to them, which may not totally wash away in a dishwasher.

Chef knives: unless your dishwasher has a dedicated rack for knives, you should avoid placing sharp knives in your dishwasher as they can nick the hard plastic.

Copper pots, pans and mugs: like many other items on this list, the harshness of a dishwasher will often tarnish copper causing its surface to dull and discolour.

Cookware with burnt-on stains: it often takes some serious elbow grease to remove cooked-on stains and burns from your kitchenware, and a dishwasher simply won’t cut it.

Crystal: while some crystal is, in fact, dishwasher safe, it’s best to err on the side of caution and keep your valuable crystal glasses and punch bowl away from your dishwasher, as they may crack and lose their sheen.


You may notice that your kitchenware includes one (or many) symbols that don’t look like the dishwasher safe ones shown above. There are many other symbols that can be used to denote various other safety precautions that go beyond the dishwasher. Below are a few common ones that you may come across:


This first symbol indicates that the material composition of the item is safe to come into contact with food. This is often confused for the symbol denoting an item is dishwasher safe. Be mindful that they’re not the same:

This symbol indicates that the kitchenware is microwave safe (this is important to note, as some products may not be oven or grill safe):

This symbol indicates the maximum and minimum temperatures to which the product can be exposed. This can be important to note if you plan on storing the kitchenware in the freezer or using it in an oven:

This symbol indicates that the item is safe to store in a freezer:

You always want to ensure that your kitchenware is in top shape and functional when you need it to be. Knowing and understanding the symbols you may find on your products is key to maintaining this functionality and their longevity. Accidentally using your dishwasher on unsafe items can result in irreparable damage both to the piece of kitchenware or to your dishwasher. If, however, you find that your dishwasher is unable to safely clean approved items, it may be time to visit a dishwasher sale near you.

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