The things you should obviously put inside your microwave oven include food and food containers.
Everything else should not be put inside your microwave because you risk ruining them and/or ruining your expensive electronic appliance.
Don’t try what the YouTube Channel about microwaving things other than food at home because they tend to ruin their microwave units at the end of their videos.
You may also like: What Can You Put in a Microwave?
What are the things you should never put in the microwave? Anything that’s not food. While we’re at it, there is the food you shouldn’t microwave either because they tend to build internal pressure and burst or go up in flames like bombs inside this type of oven!
The Things You Should Never Put In The Microwave
Long story short, the answer to the question is, “Food is good and not food is bad”. Some food shouldn’t be microwaved either, so it should instead be, “Some food is good,” instead. Don’t microwave soap, live animals that can fit the oven, and electronics, please.
Microwaving Plastics 101
To microwave or not to microwave plastic? That is the question. It’s probably the number one concern you have regarding what you can’t microwave, because all the rest of the things you shouldn’t microwave are immediately obvious and commonsensical, like rodents, CDs, or metal utensils.
Read more: Can You Microwave Plastic?
You can only microwave multi-use plastic containers with the “microwave-safe” marking. All else, from single-use takeout containers to plastic wraps, should not be microwaved with food because they could leach off of contaminants and toxic chemicals from the superheated plastic. All plastics labeled “microwave-safe” are FDA-approved for microwave use.
The Limits of a Microwave
In light of how powerful an appliance a microwave is, you should be aware that with its great power comes great responsibility and great potential for harm.
Not everything can be cooked or heated instantly like magic with an oven. For example, if you screw up with your settings, your attempt at heating or cooking pizza will result in a dry, tough crust and uneven heating all around.
Further reading: What are Microwave Safe Materials?
It’s this aspect that makes the traditional oven superior to microwaves, even with their cumbersome preheating time requirements and whatnot.
A microwave is designed to heat up, defrost, reheat, or even cook food using the effects of microwave rays on the molecules of food. Nothing more and nothing less.
One-Time Storage Containers are a No-Go
It’s right in the name. A one-time storage container shouldn’t be microwaved because it’s supposed to be used one time, usually to help with takeout and delivery of food for containment purposes.
If the one-time-use container is listed as microwave-safe (unlikely but possible), this usually means you can only microwave with it one time as well.
Most of these plastic containers must not be microwaved ever. They include items such as takeout boxes, butter or margarine tubs, and yogurt containers.
Don’t ever risk microwaving plastic, Styrofoam, or cardboard containers that don’t have a specific “microwave-safe” label. Even with that label, damaged containers should never be microwaved either.
The Dangers of Putting Just Anything Inside Your Microwave
If you were to put your tablet/iPad or smartphone/iPhone inside your microwave, you risk not only ruining the device but also the microwave itself, as shown by countless YouTube videos attempting such a foolhardy endeavor.
You’ll also risk animal cruelty by microwaving small animals like hamsters inside this oven (that’s a crime in several states and by federal or national law).
This is abusive behavior that should not be tolerated. Anything not related to defrosting, heating, reheating, or cooking food and beverages in microwave-safe containers have no business being inside a microwave oven.
Aluminum Foil and Microwaves
You can technically microwave foil if you do it correctly and you’re aware of their potential for danger. Hot Pockets have microwaveable containers lined with aluminum, after all. Many people avoid trying to microwave food with aluminum foil because it’s a fire hazard. The foil could catch fire like it’s a bushel of steel wool.
When microwaving with aluminum foil, it should only be used for shielding and with the proper instructions and recommendations of a cookbook. This is because the foil could induce arcing when nearer than 2.5 centimeters away from the metal oven walls. It should also be cut and torn into pieces to cover the thin parts of poultry or meat (its recommended usage).
Don’t Microwave Metal Containers and Utensils
Like with aluminum foil, the metal, steel, or silverware utensils you have could cause arcing or worse when placed nearer than 2.5 centimeters away from the metal walls of your microwave oven. Furthermore, accidentally leaving the spoon or fork behind with the rest of your dish can cause sparks to form.
When electromagnetic waves from the magnetron of your oven hit something metallic or reflective, this typically results in the arcing phenomenon, which is definitely a fire hazard since it produces sparks or electrical flashes. These sparks could fly and burn your food.
At worst, it could create a fire so severe it damaged your microwave. Or the device could overheat. It’s a no-no to heat canned foods because of their metal content and the fact that the sealed container can result in pressure buildup.
Brown Paper Bags, Cardboard Boxes, and Microwaves
The U.S. FDA doesn’t recommend microwaving brown paper bags, considering it an unsanitary practice. A paper bag from the grocery is made of thin paper material, unlike pizza cardboard boxes with their thicker cardboard material used to house greasy pizza and keep it warm.
Furthermore, microwaving a paper bag can lead to it catching fire and emitting toxic fumes. It’s better to use oven cooking bags instead of paper bags for heating food.
The hotness caused by microwave waves might result in the bag igniting since its material is so thin. A pizza box has thick cardboard material instead, making it more microwaveable and less likely to go up in flames.
However, if a thin cardboard container or a paper bag were to get microwaved, its ink, glue, and recycled materials can result in volatile organic compounds (VOCs) leaching into your food when exposed to high temperatures.
A Show About Things You Shouldn’t Microwave
Don’t microwave a dry sponge. It can catch fire. There’s a show named “Is It a Good Idea to Microwave This?” that covers many of the things you shouldn’t microwave, like a dry sponge or steel wool, which can easily create flames and induce the dangerous arcing effect inside the oven.
The microwave specialist of the show has tested various items for microwaving, including a CD, bleach, pencils, packaging peanuts, a bar of soap, a propane tank, a Pikachu doll, spray paint, firecrackers, and talking greeting cards. They typically resulted in explosions, sparks, flames, and melting material that somewhat or totally ruined the oven afterward.
The Cruelty of Microwaving a Living Thing
When you microwave a small animal like a hamster, puppy, mouse, or kitten, it’s not only excessively cruel. It could result in irreparable damage to the poor thing.
Obviously, microwaving an animal for a full minute will usually result in death or almost dead. It’s practically torture, to be honest.
According to anecdotal evidence, a microwaved kitten suffered from a minor burn and the inability to walk a straight line despite surviving the assault.
In the U.S., microwaving animals is covered by the Animal Welfare Act of 1966. It’s the only U.S. federal law that regulates the treatment of animals by dealers in transport, exhibition, research, and so forth.
FAQ Regarding Materials Banned from Microwaving
Here are the most frequently asked questions regarding which materials should not be microwaved at all, particularly the reasons behind why microwaving them is a bad idea. Learn more about the effects of microwave rays on certain items without experimenting on them yourself to the detriment of your electronic appliance.
What Is Arcing in the Context of Microwaving?
Arcing occurs when metal foil or silverware such as a fork or spoon is exposed to electromagnetic waves from the microwave’s magnetron. It results in sparks and electricity forming, especially if it gets into contact with your oven walls.
This is potentially dangerous because it could do more than just burn your food but also damage the unit itself.
This is why you should avoid putting metal anything inside the microwave, even if it’s just aluminum foil. The metal or reflective material reflects the microwave rays as well, leading to all sorts of unintended consequences.
Even things like a metal handle, staples on packaging, or foil on paper plates can cause arcing that could burn your food and damage the microwave by shorting out its circuitry or overheating it.
Which Food Items Shouldn’t Be Microwaved?
Grapes shouldn’t be microwaved. Microwaving them can result in a glowing plasma gas ball emerging from them due to internal pressure, which then turns into outright flames.
Use room temperature to warm up cold grapes straight from your refrigerator instead of heating them via microwave. It’s better to have tepid grapes than a fire hazard. Peppers can also catch fire due to them containing capsaicin.
You’re also discouraged from microwaving eggs with intact shells. Ditto hot dogs, sausages, and potatoes. Boiled eggs shouldn’t be microwaved either.
They also have the potential to explode due to internal pressure buildup. An egg with its shell is a sealed container that can lead to rising pressure.
You can cause a nasty egg explosion that’s hard to clean up when all is said and done. Even if a boiled egg is peeled, it can still explode when microwaved. It’s better to piece a boiled egg full of holes so that they’d serve as its pressure release points.
Why Does The Internal Pressure Rise in Certain Things When Microwaved?
Internal pressure rises in certain things such as a boiled egg, hotdogs, and sausages, or any food item that’s somehow sealed shut with eggshells or skin. This is because a microwave works by using its rays to vibrate water molecules for quick heating through friction.
Furthermore, some of the heated water can turn into steam and expands, with the expansion causing the container to swell regardless of the container type. If it’s a sealed container with loads of water like a boiled egg or a hotdog, there’s bound to be an explosion to occur unless you were to poke holes all over it to keep internal pressure from building inside it.
Why Do You Need to Pop-Out or Leave Ajar Lids on Containers When Microwaving?
You don’t seal containers properly or leave them slightly open for exactly the same reason why you don’t microwave eggs, hotdogs, or sausages.
The rising internal pressure from these foods can be simulated when you microwave anything inside a sealed container. The water expands, pressure builds, and without release, disaster can strike.
It’s imperative that you poke holes in sealed food like it’s a bad argument to serve as a pressure release for all the superheated moisture and pressure buildup. As for sealed containers, it’s best that you put the lid on the container but don’t close it completely.
Crack it slightly open or leave a bit of room for the steam and expanding moisture to escape so that your food won’t “explode” all over the inside of your oven as it gets heated up by microwave rays.
What About Other Plastic Containers? Are They Microwaveable?
Do not microwave garbage or trash bags, grocery bags, or film canisters. Just because you’ve heard of people microwaving their wet clothes in order to dry them out faster, it doesn’t mean that you should do it too or you can microwave various other non-food items.
This carries loads of risk, like arcing due to the metal zippers and buttons on a given article of clothing. To reiterate, never microwave a non-food item. Anything you don’t intend to cook or reheat for consumption should be off-limits to your microwave. Practice common sense when it comes to what can be microwaved or not.
What Happens When You Boil Water Inside Your Microwave?
The same principle of making water vibrate by contact with microwave rays is what enables a microwave oven to heat up cups of water rather fast, like in a minute or so.
Normally it takes a few minutes to half an hour to heat up water at the same temperature or all the way to the boiling point. With that said, don’t heat up an already hot cup of water.
This might cause the water to become superheated. Raising its temperature so high that it might explode upon contact with something not so hot, like a teaspoon of sugar or creamer.
What’s more, we can talk straight from experience that heating up a hot cup of water can lead to your microwave itself becoming super-hot or overheated. Like a car or a computer that’s overheating, an overheated microwave oven might cease its functions, sometimes permanently. Prevent superheating by placing a wooden chopstick in the cup to help with heat absorption.
What Are Some Non-Food-Items You Can Place Into Your Microwave?
A wet sponge can be placed in your microwave oven for microwaving, leading to disinfection. A dry sponge is a fire hazard when microwaved, though.
The moisture in a wet sponge, especially with a little dishwashing soap, can lead to it giving your microwave a disinfecting steam bath of sorts. Potting soil can also be microwaved for the sake of sterilizing it.
Use a microwavable ziplock bag to microwave dish towels, but don’t zip the bag all the way to allow it to release pressure and steam. After heating, close the zipbag up and now you have a DIY hot water bottle or bag.
Don’t heat up a rubber hot water bag because it can release toxic fumes when heated up. Anything rubber shouldn’t be microwaved because it could get set on fire or melt.
Get a microwave-safe container and fill it up with beans. Heat it up with a microwave and voila, you now have a hot water bag alternative made of beans instead of dish towels.
Additionally, you can heat up various beauty products like facial masks, hot oil conditioners, and hot wax for hair removal, but only for a few seconds. When microwaving water mixed with lemon, you can end up disinfecting and deodorizing your microwave with it a la the wet sponge trick.
Metal materials can cause sparks or explosions inside the microwave oven. Grapes can explode or cause a fire too when microwaved. Melted plastic on your food means that food is ruined. Not everything can be microwaved or is microwaveable.
While a microwave is useful enough to fulfill a variety of purposes at the push of a button, it’s not so dependable when handling other cooking styles or attempts. Read your microwave user manual or get a PDF of it off of the Internet to know how to properly use it or not.
Finally, use this guide to tell you which foods or container materials shouldn’t be put inside the microwave. Meanwhile, let common sense tell you not to put anything non-food-related into this oven. This is not a toy easy-bake oven you can play with.
- “What Materials Can Be Used in the Microwave Oven?“, Domo-Elektro.be, Retrieved December 31, 2020
- “Which Food Containers Are Safe for the Microwave?“, Real Simple, September 7, 2010
- Melanie Pinola, “What Should and Shouldn’t I Microwave?“, Lifehacker.com, October 9, 2019