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Can You Microwave Cardboard? (The Answer Will Shock You)

Everyone hates washing the piled-up dishes. When you get a chance to spare them from dirt, you’ll definitely take that shortcut.

can you microwave cardboard
Food in cardboard

If you want to heat your food quickly without necessarily creating an additional pile of dishes, perhaps using cardboard inside your microwave is a viable option you can consider.

But can you microwave cardboard anyway?

Yes. While it’s not the best idea, cardboard is microwave-safe. However, there are a few precautions that you need to have in mind such as not overheating.

Read Also: Can You Microwave Duct Tape?

Can You Put Cardboard in the Microwave?

It’s advisable not to put cardboard that contains plastic, wax, ink, or metal coating in the microwave as it can easily damage your microwave.

How Do You Microwave Cardboard?

Below are some tips on how to microwave cardboard;

  • Before you use cardboard in the microwave, check if it is labeledsafe for use in the microwave”. If you find any indications that it isn’t microwave-safe, DON’T microwave it.
  • Check if cardboard has any wax or plastic coating because the two can be unsafe should they get into contact with the heat inside the microwave.
  • Before setting the cardboard in the microwave, get rid of any plastic pieces or metallic materials, for instance, lids on the coffee cups or the plastic pizza box handle.
  • Microwave settings should be set to low to help eliminate any fire damages when heating is in progress.
  • Most dishes will take about 60 to 90 seconds to heat up, but for drinks or beverages, they should take about 120 seconds.
  • When microwaving, keep on checking your cardboard to avoid overheating. One should not leave the microwave unattended while it’s running to avoid overheating.
  • For maximum safety, place parchment paper at the bottom of cardboard to prevent it from sticking to the microwave’s surface.

How Long Can You Microwave Cardboard?

Like I said before, you shouldn’t overheat your cardboard. Simply put, if you overheat it, the spontaneous combustion can result in metallic parts or plastics releasing some chemical toxins that could be harmful to your health.

So how long can you microwave cardboard? Well, about 60 to 90 seconds could be enough if you are warming cakes. If you are warming beverages or other liquid drinks, you can go up to 120 seconds. 

If you want to microwave for a longer period, it is better you do that in shorter intervals usually between half to one minute as you restart the heating process.

What you need to have in mind is that your health comes first. There is no other way to go around this.

Before you microwave anything, make sure that you get rid of plastic, paper, or any metallic materials that may be on the board.

Can You Put a Cardboard Pizza Box in the Microwave?

Sometimes, your pizza can become cold because of the distance between the restaurant and home, or maybe you had some errands on the way. You may want to microwave it as soon as you get home.

In the process, can you use a plate or you can just make use of the pizza box?

The material for making the pizza box is cardboard. Therefore, it is very safe to microwave as long as you do not overheat it. This is the specific rule of the thump that you need to have in your mind.

Is a Cardboard Pizza Box Heat-Resistant?

Every time you talk about cookware, you cannot avoid talking about the two common terminologies: fire-resistant and heat-resistance.

  • Any heat-resistant material can stand temperatures that do not exceed 140°C.
  • Any material that can stand temperatures between 250 and 300°C is fire-resistant.

A cardboard pizza box is a material that can combust if you overheat and there you should not place it near open flames or sparks. Its ignition temperature can be around 420°C from which it will combust spontaneously.

This can be dangerous because you may set your house in flames.

Because of this, you just need to know your limits and through this, you can avoid any possible damages to your microwave or your house.

Can You Microwave Cardboard Takeout Boxes?

Yes, you can. There is nothing really unsafe about microwaving cardboard takeout boxes. Usually, the microwave temperatures will just make the cardboard hot but not to the point of setting it ablaze. Unless you did not put some food on the takeout boxes then you may experience. 

As a precaution, you should not microwave takeout boxes that have metallic handles as this may spark easily and set the whole microwave on flames.

Based on my experience in the past, I have microwaved food in cardboard takeout boxes and nothing alarming did happen.

So what can go wrong when you try it? I don’t think there’s anything that is going to happen as long as you adhere to the guidelines I have outlined above.

Remember your safety comes first each time you are preparing your meal.

Can You Reheat Food in a Cardboard Box?

Reheating your leftover food is common practice for many people. It is simple, it is fast, and it is effective.

Sometimes, we may want to reheat some leftovers. But can you reheat them in cardboard boxes? The answer is yes and no. No, because heating could melt the exterior coating of the cardboard box and this is inherently risky. The coating may contain chemical elements that may poison your food.

Yes, because if you do the right thing, you are good to go and there is absolutely nothing wrong that would happen.

Extreme heating can easily ignite a cardboard box so you should always avoid overheating it. However, note that this happens rarely.

What Happens When You Put a Cardboard in a Microwave?

You require food inside cardboard before setting it in the microwave to absorb the waves produced. Even though the cardboard is not likely to catch fire, it’s best to keep it in the microwave for a short period. This is because it can have some particles that aren’t microwave safe.

Can You Microwave Cardboard Cups?

So you have been busy on some stuff and you only come to realize that your cup of coffee is already cold. You are now wondering whether to reheat it directly on the cardboard cup or use other materials.

Is it safe to microwave cardboard cups? No, it is not safe. What makes them unsafe is how they make those cups. The plastic lining and wax on the inside lining of these cups may melt and get into your coffee to contaminate it. 

Usually, a microwave may not heat all the contents uniformly. What does this mean? It means that the dry parts of your coffee cup will suffer a greater impact. The effect of this is a warmed coffee that tastes yuck!

Or worst still, cardboard can melt, catch flames, or break.

So if you can’t make it to take your coffee when it is still hot- we are not judging, you need to find some other materials to microwave it. Perhaps some metallic material will do you good.

Can You Microwave the Paper Box?

A good number of fast foods nowadays come in paper boxes. What if they become cold before you devour them or maybe they are leftovers from sumptuous yesterday’s food?

You want to microwave the food without using your other dishes. But the question that you keep asking yourself is can you really microwave a paper box? Yes, you can. Paper boxes are generally safe to microwave as long as you do not involve too much heating. 

Again, make sure you get rid of anything such as metallic handles or any other stuff attached to it because you may not know how they will react with too much heating.

To be safe when microwaving a paper box all comes to just being a little bit cautious. And this doesn’t hurt, does it?

Does Cardboard Catch Fire When Put in the Microwave?

Putting cardboards in the microwave is never completely safe as it contains combustible materials.

When heated at high temperatures for a long time, it can catch fire pretty fast and destroy your appliance. Placing scrunched-up cardboard in the microwave can also cause sparks.

Here are a few cardboard microwaving precautions you should always consider;

  • Cardboard and paper companies are now manufacturing their products from recycled materials. Such products can contain particles that are not microwave-safe, meaning they can easily cause sparks inside the microwave. The good news is, food boxes are rarely recycled, so it should not be much of a problem.
  • Recycling has become very common nowadays. If you visit a restaurant, recycling bins are usually separate from plastic containers, so you should be very cautious when microwaving your cardboard.
  • The main reason why microwaving cardboard is safe is simply because there’s food in the container. Microwaves heat up the juices in the food while ensuring the cardboard does not overheat.

If cardboard is empty, the microwave heats up cardboard container drying it out to the point that it catches fire.

Always ensure there’s food inside cardboard container before setting it in the microwave to avoid damaging your appliance.

Final Thoughts

Most of the time, we like avoiding too much washing, because seriously, who likes doing a lot of dishes?

When we get a shortcut of microwaving our leftovers or your cold food without using any of our utensils, we normally take that. But the question that you must have is how safe is that practice? You want to know that you are doing the right thing to avoid problems.

Cardboard boxes are generally safe to microwave so you need not worry whether or not you can use them. But like we stated as a general rule, being cautious greatly contributes to your overall safety.

Do not overheat any of these materials because most of them have lower melting points and they may catch flames if you overheat them.

You should not microwave a cardboard box for over 120 seconds because you may be risking overheating it.

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