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Don’t Put These 8 Things in the Microwave

Someone uses a microwave
Zyn Chakrapong/Shutterstock.com

The microwave is an incredibly convenient kitchen appliance that has revolutionized how we cook and heat food. However, not everything can be safely microwaved. Some foods and items can be dangerous to put in this appliance, posing a risk to your health and kitchen appliances. Here are eight things that you should never stick in the microwave.

Styrofoam Containers

Someone holding styrofoam containers

When you order food delivery or take home leftovers from a restaurant, that food will typically come in a styrofoam container. Styrofoam is a type of plastic that is often used for food packaging.

While using these containers for microwaving your leftovers may seem convenient, it can be hazardous. When heated, the styrofoam can melt and leach chemicals into your food, which can be harmful to your health. Additionally, the heat can cause the container to warp and spill hot food or liquid, causing burns or damage to your microwave.

Instead, use microwave-safe glass or ceramic containers for reheating your food. Some takeout containers are microwave-safe, but they will be labeled if they are. If you aren’t sure, play it safe and reheat your leftovers in another container.

Ailtec Glass Food Storage Containers with Lids

These containers are safe to use in the microwave.


A bowl of grapes

There aren’t a lot of situations where you would want to microwave a grape, but if you ever have the inclination, ignore it.

When grapes are cut in half and placed in the microwave, the small size and shape of the grape halves, combined with the water and salt content inside the grape, can create a type of plasma that acts as a conductor of electricity. This can ignite a spark, which can lead to a fire, posing a danger to your safety and your home.

COMFEE' EM720CPL-PM Countertop Microwave Oven

A great affordable microwave (but still not safe for grapes).

Hard-Boiled Eggs

Hard-boiled eggs
Brent Hofacker/Shutterstock.com

Hard-boiled eggs are typically eaten cold, but some people might want to heat them up before adding them to a bowl of ramen or another hot dish. However, this is another food that needs to stay out of the microwave unless it has been cut into pieces.

Whole hard-boiled eggs may burst in the microwave and cause a huge mess. Eggs with the shell on can also build up steam inside and explode while cooking. Even if the egg doesn’t explode, the pressure from the steam inside the egg can cause it to burst open when you remove it from the microwave, releasing scalding hot water and potentially burning you.

The safer way to hard boil an egg is to place it in boiling water and cook it for 9-12 minutes, depending on how hard you want the yoke to be. If you want to cook eggs in the microwave, make sure they are out of the shell. This typically works best with omelets.

DASH Rapid Egg Cooker

The easiest way to make hard-boiled eggs.

Plastic Containers

Stacks of plastic containers

Similar to styrofoam, plastic containers can release harmful chemicals when heated in the microwave. This is especially true for containers that are not labeled as microwave-safe. The heat can cause the plastic to break down, leaching chemicals into your food that can be hazardous to your health.

If you store leftovers in plastic containers, move them to a glass or ceramic container before heating them in the microwave. These containers don’t have harmful chemicals in them that can impact your food.

Aluminum Foil

Someone uses aluminum foil

it is generally not safe to put aluminum foil in the microwave. When microwaves come into contact with metal, they can create sparks and potentially start a fire. This is because metal reflects microwaves and causes an intense electrical current to flow through the metal, which can lead to a spark.

The U.S. Food and Drug Administration does say that it is safe to put small amounts of aluminum foil in the microwave for short periods of time. However, to play it safe, stick to microwave-safe lids instead of foil when covering food.

Tovolo Vented Collapsible Medium Microwave Cover

Use this to cover your food instead of aluminum foil.

Metal Utensils

A silverware drawer
Vladyslav Lehir/Shutterstock.com

Using metal utensils in the microwave is a big no-no. Metal reacts to microwaves the same way as aluminum foil, but even more severely.

Sparks from metal utensils can ignite a fire or damage the microwave. Metal can also become very hot when heated in the microwave, which can burn you if you touch it or cause it to ignite nearby materials.

To avoid any risk of fire or damage to your microwave, it’s best to use microwave-safe utensils made from glass, ceramic, or plastic when heating food in the microwave. If you accidentally put a metal utensil in the microwave and it starts to spark, turn off the microwave immediately and remove the utensil using oven mitts or tongs.

Utopia Kitchen Bamboo Silverware Organizer

For organizing those utensils.

Hot Peppers

An assortment of hot peppers

Microwaving hot peppers may not necessarily be dangerous, but it can cause the peppers to release capsaicin, which is the compound that makes peppers spicy. This can cause the fumes and steam from the peppers to irritate your eyes, nose, and throat, which can be uncomfortable and even painful.

If you need to cook hot peppers for a recipe, use a pan, skillet, or the oven. If you do decide to microwave hot peppers, it’s best to do so with caution and take care to avoid inhaling the fumes or getting burned by the hot juices.


Slicing a loaf of bread

While putting bread in the microwave isn’t dangerous, it also isn’t a great idea because it can make the bread soggy and rubbery. This is because the microwave works by heating up the water molecules in food, and bread has a high water content. When you microwave bread, the moisture inside the bread can turn into steam, which can make the bread soggy.

If you need to reheat bread, use a toaster or an oven. The dry heat of these warming methods won’t cause your bread to get rubbery, although you will need to watch the bread to make sure it doesn’t dry out.

BLACK+DECKER 2-Slice Extra-Wide Slot Toaster

Plenty of room for toasting slices of bread.

By being mindful of what you put in the microwave, you can avoid potential hazards and keep yourself and your kitchen safe. Keep these items out of the microwave and stick to safer cooking and warming methods.

Anne Taylor Anne Taylor
Anne Taylor is a writer with a BA in Journalism and a passion for storytelling. Her work has been published on a variety of websites including Mental Floss and Well + Good, and she recently published her first novel, What it Takes to Lose. When she's not writing, Anne loves to travel (19 countries and counting), spend time outside, and play with her dog, Pepper. Read Full Bio »
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