I learned earlier than most that there are things you should never put in the oven—when I was a pre-teen, I heated a plastic wrap–covered meal in the oven only to watch it burst into flames (shout-out to my older brother who helped me eradicate the mini fire before it spread). After that occasion, my mother sat me down to remind me of the dos and don’ts in the kitchen, including all the things you should never—ever—put in the microwave. At first glance, you’d think this appliance was the least likely to be dangerous because you never actually see its heating mechanism. But just because it’s not as obvious doesn’t mean that the potential for danger is any less (after all, we can still get a sunburn on a cloudy day).
If you find yourself doubting how severe kitchen fires can be, the National Fire Protection Association reports that cooking was the number one cause of house fires and the third cause of fire-related deaths at home between 2009 and 2013. And microwave faux pas don’t just lead to fires—they can also cause harmful substances to be released into the air. On top of that, they’re responsible for hard-to-clean messes, which is just one more reason you should familiarize yourself with things you should never put in the microwave. So go on—keep reading to see a list of those 11 things (then commit them to memory).
While tinfoil (as I like to call it) is fine in the oven, it is not okay in the microwave, so you must make sure you take it off your food before nuking begins. The appliance’s inside is made out of metal, and it reflects microwaves that allow your food to heat up. The problem is that when you put another metal (aka foil) inside of the machine, the waves reflect off the metal, causing it to burst into flames.
I know quite a few people who make scrambled eggs in the microwave at work for breakfast. (I’m intrigued but can’t say I’d do it myself.) The problem occurs when you’re attempting to cook an egg that’s still within its shell. The result is that the steam rises within the shell—and poof!—the high temps cause the egg to explode into a runny mess.
You know those little white takeout boxes that sticky rice often comes in? (Yes, the ones with the itsy, bitsy metal handles). They are pretty hazardous when nuked because they also contain metal (see what happens above, plus add in some potential for sparking).
If you’re heating up a dish containing hot (read: spicy) peppers, it’s definitely worth doing it in the frying pan or oven. Other than their potential to go ablaze inside the microwave, the peppers can also release their chemicals when you open the door. You may feel as though you’re going to choke from the chemical release into the air, or the juice can accidentally go into your eyes—and it can have the same effect as pepper spray.
Heat is known to kill everything, including bacteria. This is why some people think it’s a good idea to put their dry sponges from the sink in the microwave for a few minutes, thinking they’re getting rid of all of the germs. Although it will do that, it can also cause some serious trouble. “If sponges are dry, there’s no water to attract energy, and the sponges themselves will attract energy and can catch on fire,” says Sharon Franke, director of the Kitchen Appliances and Technology Lab at the Good Housekeeping Institute. Here's a trick: Submerge your sponge in water first before putting it in the microwave.
Did you know that some tableware from years ago actually contained lead? Well, more than 40 years ago the FDA put its foot down, but that doesn’t mean your antiques don’t contain it. The plates and other dining ware should be fine to eat off of—you just don’t want to heat it in the microwave because lead can potentially seep into your food.
Sometimes it can feel like waiting for meat to defrost in the fridge is literally going to take forever. When that happens, we often opt to put it in the microwave to thaw it out. The issue with this is that if the meat doesn't rotate in the microwave, it can lead to an uneven distribution of heat that can cause bacteria to grow. When meat hits a "danger zone" of 40ºF to 140ºF, bacteria can multiply at an extremely fast rate. So the next time you try to speed up this process, it might be worth thinking again.
There’s a reason everyone says not to put plastic containers in the microwave: It’s due to the chemicals that can be released into your food when heated (BPA is only one of them). A study actually found that 95% of 450 plastic products (including plastic bags and baby bottles) actually released chemicals similar to estrogen when heated.
If you’re one of those travel-mug-toting people who like coffee from home on their commute, do yourself a favor and pour your java into a mug before reheating it later. The stainless steel in the mug stops the microwave from heating up the beverage and can actually cause damage to your appliance at the same time. If it’s plastic, always check the bottom to see if it’s deemed “microwave safe” before nuking.
But why not, since I can microwave popcorn in a bag? Well, those bags are treated with a material that absorbs the waves emitted by your appliance. Regular paper bags (from the grocery store, sandwich bags, etc.) can actually release toxins when heated. There’s also the possibility that the bag could light on fire while heated.
Ever accidentally get some cash wet? Yes, it happens to the best of us, but the microwave is not the answer. Paper (see above) can catch on fire, and some people have reported that their dollars burned a bit in the appliance when trying to dry them out. In fact, more people than you think actually do this—a worker at the Office of Currency Standards has said that it’s one of the biggest problems they see.
Now that you’ve read this list of things to never put in the microwave, your kitchen should be a much safer place. And remember, when in doubt always look it up before nuking something new.