6 Things You Should Never Put in the Microwave

The microwave is one of the most convenient kitchen appliances ever invented. It reheats food in seconds, melts chocolate, warms milk, and even cooks entire meals.

But while it’s undeniably useful, the microwave can also be surprisingly dangerous when used incorrectly. Some items can release toxins, cause fires, explode, or even damage the appliance beyond repair.

To keep your kitchen safe — and avoid harmful accidents — here are six things you should never put in the microwave under any circumstance.

1. Metal Objects — Sparks, Fire, and Damage Guaranteed

Metal and microwaves are a dangerous combination.

Whether it"s aluminum foil, metal spoons, stainless steel plates, or takeout containers with metallic edges, any metallic object can cause sparks, loud popping sounds, and even start a fire.

✔ Why metal is dangerous:

Microwaves bounce off metal instead of passing through it

This causes sparks and electrical arcing

It can ignite paper or plastic nearby

It may permanently damage your microwave’s internal components

✔ Items you must avoid:

Aluminum foil

Metal cutlery

Stainless steel bowls

Foil-lined containers

Metallic-trimmed mugs

✔ Safe alternative:

Always transfer your food to microwave-safe glass or ceramic dishes before heating.

2. Plastic Containers That Aren’t Microwave-Safe — Toxic Chemicals in Your Food

Not all plastic is created equal.

Many plastic containers, especially cheap ones, release dangerous chemicals when heated. These chemicals — particularly BPA and phthalates — can leach into your food and affect hormonal health over time.

✔ Why unsafe plastics are harmful:

They melt or warp

They release toxic chemicals

They contaminate your food

They may ruin the taste and smell of meals

✔ Unsafe plastic items include:

Disposable takeaway containers

Yogurt tubs

Plastic water bottles

Cheap food storage boxes

✔ Safe alternative:

Look for labels such as:

“Microwave-safe”

“BPA-free”

Symbols showing a microwave icon

When in doubt, use glass — it’s the safest option.

3. Eggs in Their Shell — A Guaranteed Explosion

Microwaving whole eggs is one of the most common kitchen mistakes.

The intense heat creates steam inside the eggs faster than it can escape, causing the egg to explode violently.

✔ Why eggs explode:

The yolk heats unevenly

Pressure builds inside the shell

The shell cannot release steam

The result is an explosive mess

✔ Risks include:

Burns from hot egg splatter

A microwave covered in egg

Damage to the appliance

✔ Safe alternative:

If you want microwave eggs:

Crack them into a bowl

Pierce the yolk

Cover the bowl

Never microwave eggs in their shells — it’s not worth the risk.

4. Hot Peppers — Chemical Steam That Can Burn Your Eyes and Throat

This one surprises many people.

Microwaving hot chili peppers, especially jalapeños or habaneros, can release capsaicin into the air. Capsaicin is the chemical that gives peppers their heat — and when vaporized, it acts like pepper spray.

✔ Why peppers are dangerous in microwaves:

Heat causes capsaicin to become airborne

Opening the microwave releases a spicy cloud

It can cause coughing, burning eyes, and throat irritation

✔ Symptoms may include:

Watery eyes

Difficulty breathing

Severe burning sensations

Sneezing

✔ Safe alternative:

Cook or roast hot peppers on a stove or in an oven instead.

5. Styrofoam Containers — A Hidden Chemical Hazard

Styrofoam is commonly used for takeout food, but it’s one of the worst materials to put in the microwave.

✔ Why Styrofoam is dangerous:

It melts easily

It leaks harmful chemicals

It contaminates food

It warps and collapses under heat

Styrofoam contains styrene, a chemical linked to hormone disruption, headaches, and long-term health issues.

✔ Safe alternative:

Always transfer your food to a microwave-safe glass bowl before heating.

6. Empty Plates or an Empty Microwave — A Recipe for Appliance Damage

Turning on a microwave with nothing inside it may seem harmless, but it can actually destroy the appliance.

✔ Why this is dangerous:

Microwaves have nothing to absorb their energy

The waves bounce around internally

This overheats the microwave’s magnetron

It may cause smoking, sparks, or complete failure

✔ Always ensure:

There is food, liquid, or a microwave-safe item inside

Never run the microwave empty for “testing”

✔ Bonus tip:

Microwave a cup of water next to small items to protect the appliance.

🌟 Bonus: Items People Think Are Microwave-Safe but Aren’t

Travel mugs with metal interiors

Paper bags (can release toxic fumes)

Cold-storage plastic bags

Thin plastic wraps that melt

Some ceramics with metallic glazes

Always double-check labels or err on the side of caution.