How to identify containers that can be used in the microwave, dishwasher, and oven

The most frequently asked question regarding pottery is "Can it be used in the microwave?"

I want to warm up my favorite mug, but is that okay? What should I do if it breaks? There are times when you think like that.

In this article, we will explain how to tell which containers can be used in the oven, as well as which ones can be used in the microwave, as well as which ones can be used in the dishwasher.

 What should I do in times like this in my daily life? Please refer to it when you are confused.

How to identify dishes that can be used in the microwave

Microwave ovens heat food by generating electromagnetic waves called microwaves.

As a general rule, metals that reflect electromagnetic waves and plastics that are not heat resistant cannot be used. (There are exceptions)

In other words, the way to tell which pottery you can use in the microwave is by its material.
The important thing is what the container is made of.

You can use items that are resistant to heat and made of materials that are not affected by electromagnetic waves.

However, please use the product according to the instructions of the creator, such as the artist or pottery manufacturer.

Below, we have summarized the containers that can and cannot be used in the microwave.

Containers that can be used in the microwave


Ceramics are fired in a kiln at a temperature of over 1000℃. Since it is a material that allows electromagnetic waves to pass through, it can be used for general purposes.

However, depending on the glaze and manufacturing method used, the bottom of the vessel may become quite hot and may be unusable, so be sure to check the labeling on the product.

*However, the following cannot be used.
・Things with cracks or scratches
・Things with metal or colored pictures used for surface decoration
*There is a risk of sparks or paint peeling off.

Heat-resistant glass

The glasses of Nakagawa Masashichi Shoten in the photo are made of heat-resistant glass

Pay attention to the labeling on glass containers! T

According to the Household Goods Quality Labeling Law, glass containers that can be used in a microwave are labeled as ``for microwave use.''

If this label is displayed, it means that the product can withstand a temperature difference of 120℃ or more.

Do not use glass products that are not labeled as ``microwave safe'' in the microwave.

Glass containers that can be used in the microwave are also labeled as ``heat-resistant glass utensils'' or ``super heat-resistant glass utensils'' (temperature differences of 400℃ or more are possible).

Plastic or silicone containers with heat resistance of 140℃ or higher

There is an impression that plastics in general cannot be used, but as long as they are heat resistant, they are OK.

According to Japanese Industrial Standards, containers that can be used in the microwave must have a heat resistance temperature of 140 degrees or higher.

Nowadays, there are plastic containers with elaborate designs. It's nice to be able to warm it up and serve it as is.

Plates that cannot be used in the microwave

Metal container

Metals reflect microwaves and create sparks, which can cause fires.

Even a single iron wire can lead to an accident, so please do not use it in a microwave oven.

Recently, paints that do not reflect when exposed to electromagnetic waves have been developed, so some of them can be used in the microwave.

In addition, there are an increasing number of containers whose surfaces are coated with mica, which does not reflect electromagnetic waves.

Plastic container

Users made of polyethylene, melamine, phenol, and urea resin can be deformed by radio waves.

Similarly, plastic containers with a heat resistance of less than 140℃ will melt.

Also, some plastic utensils that double as cooking utensils have heat-resistant bodies, but lids that are sensitive to heat. Please check before use.


Wood products such as lacquerware contain a lot of carbon, and there is a risk of burning or catching fire if you put them in the microwave. Also, the paint may peel or crack.

However, recently there are also lacquerware made of synthetic resin that can be used in the microwave.

Glass container without heat resistance

Cut glass and tempered glass can melt or break.

Precautions when using a microwave oven

Be careful of temperature difference

Even if the pottery is resistant to heat, it may crack or chip if subjected to sudden temperature changes.

Be careful when handling the microwave and do not wash it immediately after using it.

Similarly, make sure to let cold containers that have just been taken out of the refrigerator reach room temperature before putting them in the microwave.

Also, if there is not enough food in the container, the temperature of the container will rise rapidly and it may break. Empty burning is strictly prohibited.

Be careful when reheating dishes that use a lot of oil

When heating foods that are oily or covered in sauces that are high in sugar or salt, the temperature tends to reach high temperatures.

For this reason, use pottery or porcelain, or one that can withstand a temperature of 200℃ or higher.

Please be careful as plastic containers may melt.

Pay attention to the wattage

Some modern microwave ovens have high wattage. Please follow the handling instructions and use the designated time.

How to distinguish between pots that can be used in the oven

Difference between “microwave safe” and “oven safe”

Microwaves and ovens both heat food. So, don't you think that anything that can be used in the microwave can also be used in the oven?

However, microwave ovens and ovens have different heating methods.

Microwave ovens heat products by using radio waves to rub the molecules of the food. Ovens use heat to heat the food inside.

You need to choose a container that can withstand heat of around 120 to 140 degrees Celsius in the microwave and around 300 degrees Celsius in the oven. Even though they are called heat-resistant dishes, you need to be careful as there is a difference between those that can be used in the microwave and those that can be used in the oven.

Below, we have compiled a list of ``Usable and Unusable Utensils'' in the oven.

Oven-safe containers

Basically, use heat-resistant dishes that are labeled as oven-safe.
* Items with colored pictures, cracks, or gold/silver patterns cannot be used.

・Heat-resistant glass container

Plates that cannot be used in the oven

・Plastic/silicone container


・Wood and bamboo containers

・Metal vessels/cutlery

Things that can be used in the microwave but not in the oven
Heat-resistant plastic containers with a heat-resistant temperature of 140℃ or higher

How to identify dishes that can be used in the dishwasher

A dishwasher makes everyday housework easier. However, depending on the pottery, it may get scratched, or the special detergent may ruin it.

Many of the artist's containers are recommended to be washed by hand (no dishwasher allowed).

For this reason, we generally recommend washing by hand, but what happens if you put it in the dishwasher?

I tried various dishes in my dishwasher at home.

As a result, there was no case that ``it would definitely break if I put it in.''

So hand washing is recommended, but it is generally washable. That's the conclusion.

For example, when washing clothes, even though the instructions say to wash them by hand, I think there are many people who put their clothes in a laundry net and wash them in the washing machine.

It's similar to that, it's faster than washing by hand, and there's a slight risk of damage, but it doesn't mean you can't wash it (but at your own risk!).

However, this cannot be used! There is also a reason.

The key to determining whether a product can be used in the dishwasher is temperature and water flow.

From now on, we have listed the containers that cannot be used in the dishwasher. When using the dishwasher, be careful not to damage the utensils or cause injury.

Plates that cannot be used in the dishwasher

Cracked tableware (cracked pattern, stained glass-like tableware)

Moisture seeps through the cracks, causing mold and cracks.

Wooden container

Drying at high temperatures for a short period of time after absorbing moisture may cause distortion, cracking, deformation, and discoloration.


Hot air drying may cause distortion and cracks. Also, washing at high temperatures may cause discoloration and peeling.

Items with gold leaf or overpainting may react with the alkaline components of special detergents and discolor.

Metal container

・Silver, aluminum, copper: The surface may turn white or darken due to the ingredients of the special detergent.

・Gold and platinum: May react with special detergents and cause discoloration.

・Tin: Oxidizes and corrodes.

Tempered glass container

Due to sudden temperature changes, it may suddenly shatter and be damaged.

Damage inside the dishwasher may cause malfunction and may result in injury. However, heat-resistant glass can be used.

Crystal glass, cut glass

It is not suitable for dishwashers as it is susceptible to sudden temperature changes and shocks.

The surface becomes white and cloudy because it contains lead.

Sake bottle or bottle

Since the mouth is small, the spray cannot reach inside and cannot be washed. We recommend hand washing with a stick brush or sponge.

Utensils with a heat-resistant temperature of 90℃ or less

Resin products that do not have heat resistance temperature indications may become deformed or discolored due to the influence of heat.

Lightweight container

It is best not to use lightweight containers such as plastic spoons and lids.

If it falls on the heater cover, it may cause smoke, scorch, deformation, or odor.

Use the special accessory basket that comes with the dishwasher for small items that are easily blown away, such as the partitions of heavy boxes.

Items that cannot be washed with special detergent

Please check the information on the detergent container or the detergent manufacturer.

Be careful how you load the dishwasher

For brittle and easily chipped pottery, light pottery, and sharp-shaped pottery, be careful not to move them or hit other pottery.

Colored or gold and silver colored porcelain may be scratched by strong water flow.

Dishwasher-specific detergents may cause discoloration, so we recommend hand-washing delicate painted vessels.


Below is a list of containers that can be used in the microwave, oven, and dishwasher.

If you are unsure whether or not you can use it, please read here.

Range possible Ceramics, heat-resistant glass, heat-resistant plastic
Oven safe Heat-resistant ceramics, heat-resistant glass, metal materials (stainless steel, aluminum) td>
Dishwasher safe Ceramics, heat-resistant glass, stainless steel

* Items with decorations such as tempered glass, cut glass, gold and silver colored items, thin items, and items that are sensitive to heat are not acceptable.


Microwave ovens and dishwashers are essential to daily life. It would be convenient if you could just put the utensils in without worrying about anything.

By reading this article, you will be able to understand what materials are used for pottery that are resistant to heat. Please use this as a reference when choosing a pottery that is easy to clean and cook with.