15 Things You Should Never Put in the Microwave

1. Metal

Metal and microwaves simply do not mix. Metal reflects microwave radiation instead of absorbing it, which can lead to sparks, electrical system damage, and even fires. Never microwave any metal objects, including aluminum foil, utensils, plates, bowls, jewelry, twist-ties, Takeout containers, etc.

2. Styrofoam

Heating up Styrofoam containers and cups is a big no-no. Styrofoam contains benzene, which is a carcinogen. Heating Styrofoam releases toxins and can melt the containers, possibly contaminating your food. Opt for glass or ceramic containers instead.

3. Plastic Bags

Plastic bags can easily melt or burn when microwaved, releasing toxic fumes into your food. Never microwave plastic bags, plastic wraps, produce bags, or other thin plastic packaging. Remove food from plastic bags before heating.

4. Paper Products

Paper towels, napkins, parchment paper, grocery bags, and other paper items can ignite very quickly in the microwave. The thin material dries out rapidly and can catch fire. Avoid microwaving any paper products, as the fire risk is very high.

5. Foods with Skins or Peels

Foods with thick skins or peels like potatoes, tomatoes, peppers, hot dogs, sausages, and eggs can burst open when microwaved. The steam that builds up inside has nowhere to escape. Always poke holes or slit the skin of these foods before heating to prevent explosions.

6. Dried Herbs and Spices

Dried herbs, spices, cloves, nutmeg, paprika and other seasonings can ignite or create sparks in the microwave. Always mix spices into the food rather than sprinkling directly on top. And never heat up a spice jar or shaker!

7. Brown Paper Bags

Regular brown paper lunch bags are not meant for microwaving. They can easily catch fire since the material dries out quickly. Use designated microwave-safe paper products instead. Never try to improvise with other paper materials.

8. Hard-Boiled Eggs

Hard-boiled eggs should not be microwaved in their shells. Pressure can build up and cause the egg to burst explosively. Always remove the shell before reheating hard-boiled eggs. Better yet, don’t microwave them at all.

9. Hot Peppers

Hot peppers such as jalapeños, habaneros, and Anaheims can unexpectedly explode when microwaved. The intense heat in the pepper seeds and membranes builds pressure rapidly. Always slice peppers open before heating to allow steam to vent.

10. Grapes and Raisins

Grapes, raisins, and other dried fruits have high sugar content. When microwaved, they can dehydrate quickly and smoke or catch fire. Always pierce skins of fruits and vegetables before heating. Avoid dried fruits.

11. Frozen Meats

Thawing frozen meats at full microwave power can lead to uneven cooking. The edges may begin to cook while the middle stays frozen. Defrost using lower power levels or by thawing overnight in the refrigerator instead.

12. Rice and Pasta

Dry rice, pasta, barley, oats, and other grains can overheat very quickly in the microwave. The small granules heat too rapidly and unevenly. Cook grains the traditional stovetop method for best results.

13. Bread and Tortillas

Pita bread, tortillas, pizza crust, and other bread items can become tough, rubbery, and unpleasantly chewy when microwaved. Use your oven or toaster oven to heat breads with better results.

14. Wheat Bags and Hot Packs

Those microwavable heat packs and neck wraps often contain wheat, flax or other grains that can catch fire or spark when heated too long. Follow all manufacturer instructions carefully. Don’t overheat.

15. Baby Formula and Breast Milk

Never warm breast milk or baby formula in the microwave. The heat applied can be uneven and create hot spots that could burn the baby. Always use warm water instead for gentle, even warming.

The microwave oven provides fast, convenient cooking and reheating. However, caution is advised when considering heating certain foods and materials that can create safety hazards. Following these microwave safety guidelines can help prevent fires, explosions, burns, toxins, and ruined food. When in doubt, don’t microwave it!

Frequently Asked Questions About Microwaving Safety

What types of materials should you avoid putting in the microwave?

You should avoid putting metal, aluminum foil, utensils, paper products, plastics, Styrofoam, herbs, spices, food with skins/peels, eggs in shells, and hot peppers in the microwave due to fire and burn risks.

Why can metals cause problems in the microwave?

Metals reflect microwave radiation rather than absorbing it, leading to problems like sparks, damage to the microwave itself, and fires.

What may happen if you microwave food with thick skins or peels?

Foods like potatoes or hot dogs can potentially burst or explode in the microwave as steam builds up pressure inside. Always poke holes in such food before heating.

How can you prevent plastic bags from melting in the microwave?

Never microwave any plastic bags or wraps. The material can melt from the heat, leaching chemicals into food. Remove food from plastic wrapping before heating.

Why shouldn’t you microwave an egg still in its shell?

Pressure can make hard-boiled eggs in the shell explode when microwaved. Always remove the shell first to allow venting and prevent a mess.

What could go wrong with microwaving dried herbs and spices?

Dried seasonings contain oils that can heat rapidly and potentially ignite or create sparks in the microwave, leading to fire.

How can you safely microwave hot peppers?

Slice hot peppers open first before microwaving to allow steam to vent out. Otherwise, pressure buildup can cause the peppers to unexpectedly explode.

What might happen if you microwave bread products?

Breads and tortillas can become unpleasantly tough, chewy, and rubbery in texture when microwaved. Use your conventional oven instead.

Why should you avoid microwaving frozen meats?

Microwaving at full power can partly cook frozen meats while the middle remains frozen, leading to uneven cooking. Defrost first.

By understanding proper microwave safety and avoiding hazardous materials, you can continue enjoying the speed and convenience of microwave cooking without worry. Be cautious and use common sense whenever trying to microwave questionable foods or items. When in doubt, don’t microwave it!


Microwave ovens provide a fast and easy way to heat up leftovers or prepare quick meals. However, certain items should never be placed inside a microwave due to serious safety concerns. Metals, plastics, paper products, dried herbs and spices, eggs in shells, and other materials can catch fire, melt, create harmful fumes, explode, or become damaged when microwaved. It’s important to follow all manufacturer instructions and use extreme caution with questionable items. Your safest bet is to stick to microwave-safe materials and dishes for trouble-free heating. Trust your intuition – if anything seems risky, just don’t microwave it! Following these important safety guidelines can help ensure your food – and your appliance – stays safe each and every time.