Microwave Sparking and Burning Smell: Fix It Fast and Safe

During dinner last night, my microwave suddenly sparked and gave off a burning smell. It scared me! If this ever happens to you, don’t ignore it. This problem can be dangerous but also easy to fix. In this article, I’ll explain why microwaves spark and smell like something is burning — and how you can stay safe at home.

Check for Any Metal Inside

The first thing you should do is open the microwave and look inside carefully. Many people don’t know that even a small piece of metal can cause sparks. Metal doesn’t belong in a microwave. When metal is heated in a microwave, it causes electric sparks. That’s what makes it so dangerous.

Sometimes, you may forget to remove the foil on leftover food. Or maybe the plate or bowl has a silver or gold rim. That shiny part is metal. Some frozen meals also come with metal inside their tray. Even a tiny twist tie or a small fork left inside by mistake can make your microwave spark and smell like it’s burning.

I remember once I reheated pizza with the aluminum foil still stuck on the bottom. Within seconds, the microwave lit up with blue sparks. I immediately stopped it. Luckily, nothing caught fire, but the smell lasted for hours.

It’s also important to know that some microwaves come with metal racks. These racks are okay only if they are made for your microwave and used the right way. If they move or touch the side of the microwave, they can still spark.

Always double-check the plates, mugs, and utensils you put inside. Make sure they are microwave-safe. Avoid anything with metal parts, gold trim, or foil.

• Never put aluminum foil inside
• Don’t use dishes with metal rims
• Remove twist ties from food packaging
• Check frozen meals for hidden metal parts
• Use only microwave-safe plates, cups, and bowls

Clean Food Debris or Grease Buildup

Leftover food and grease inside your microwave can also make it spark and smell like it’s burning. Over time, food spills or grease splatters stick to the walls, ceiling, or turntable of the microwave. When you use it again, those stuck-on bits heat up and may catch fire.

Sometimes, we forget to clean up small messes inside the microwave. A few popcorn kernels, a splash of soup, or a piece of melted cheese may seem harmless. But once they dry and get heated again, they can cause serious problems. I once ignored a few sauce spots after reheating pasta, and the next day, I saw smoke and sparks. It smelled like burnt plastic.

The best way to prevent this is to clean your microwave regularly. Use warm water and mild soap. You can also use a mix of vinegar and water. Just heat a bowl of that mix for two minutes, and the steam will loosen all the stuck food. Then wipe it with a soft cloth or sponge.

Don’t forget to clean the ceiling, walls, door edges, and the rotating plate. If your microwave has a vent or filter, check that too. Grease can build up there over time.

Even a few crumbs or drops of grease near the magnetron cover can start sparking. That’s the part where the microwave sends out the heat waves. So, keep it clean.

• Clean after every few uses
• Use steam cleaning with vinegar and water
• Wipe all surfaces inside, not just the plate
• Check for grease near the vent or cover
• Keep the turntable and roller clean too

Inspect the Waveguide Cover

The waveguide cover is a small panel inside the microwave. It’s usually on the side wall. This cover helps guide the microwaves into the oven area. It’s made of a thin, cardboard-like material. If this cover gets dirty, greasy, or damaged, your microwave can spark.

Many people don’t know about the waveguide cover. It’s easy to forget. But over time, food splashes or grease can stick to it. That makes it hard for the microwave waves to pass through, and instead, they bounce back, creating sparks and burning smells.

If the cover is dark, burned, or has holes, you need to replace it. I once saw black burn marks on mine, and I knew something was wrong. I got a new one for a few dollars, and my microwave worked fine again.

To inspect it, unplug the microwave and open the door. Look on the right or left inner wall for a small rectangle panel. If it looks dirty or burnt, it’s time to clean or replace it. Don’t scrub it too hard — it’s fragile.

You can buy a new waveguide cover online or at an appliance store. Make sure it fits your microwave model. If you’re not sure how to replace it, ask a repair technician.

• Find the waveguide cover inside the microwave
• Check for grease or black burn marks
• Replace if it’s cracked, burnt, or damaged
• Don’t use the microwave if the cover is missing
• Always unplug before checking or cleaning it

Examine the Turntable and Its Parts

Your microwave’s turntable helps heat your food evenly. But if the glass plate, roller ring, or turntable motor is damaged or out of place, it can cause problems like sparks or strange smells.

First, take out the glass plate and look at it carefully. Make sure there are no cracks or chips. If it’s broken, it might move oddly or rub against metal parts, causing sparks.

Then check the roller ring — that’s the round plastic part with small wheels under the glass. If the wheels are dirty or stuck, the plate may not spin properly. This can cause uneven heating or overheating in one spot, leading to burning smells.

The motor under the turntable also needs to be quiet and smooth. If you hear loud grinding sounds or the plate stops moving, the motor might be broken.

Once, my microwave had a stuck roller ring. The plate tilted during heating, and the edge touched the microwave wall. It sparked like crazy. I cleaned the ring, fixed its position, and everything went back to normal.

Cleaning and aligning these parts can fix the problem quickly. Use a soft cloth and soapy water. Make sure everything is dry before putting it back.

• Inspect the glass plate for cracks
• Check the roller ring and clean its wheels
• Make sure the turntable spins freely
• Listen for grinding or motor noise
• Fix or replace damaged parts right away

Look at the Microwave Door and Seal

The microwave door and its seal play a big role in keeping the heat inside. If the door doesn’t close fully or the seal is damaged, the microwave may not work right. Heat may escape, and that can cause burning smells or even sparking in rare cases.

Open and close the door slowly. Does it click shut smoothly? Is there any gap or loose area? The rubber or plastic seal around the door should be clean and not torn. If there’s food stuck in the seal or hinge area, it can stop the door from closing tight.

I once found a piece of popcorn stuck in the corner. The door wouldn’t shut properly, and my microwave started acting weird. Cleaning that out fixed everything.

Also, never slam the door or pull it open too hard. That can damage the latch or hinges. If the latch doesn’t hold the door tight, the microwave might try to work with the door open — and that’s very dangerous.

Keep the door clean with a soft cloth. Don’t use harsh chemicals. If the seal is broken or worn out, you can replace it or ask a repair person to do it.

• Look for food stuck in the door seal
• Make sure the door shuts fully
• Don’t slam or yank the door
• Replace damaged seals or latches
• Clean the door and edges gently

Check for a Faulty Magnetron

The magnetron is the heart of your microwave. It creates the microwave energy that cooks your food. If this part is damaged or worn out, it can cause sparks, loud humming sounds, or a burning smell.

This part is inside the microwave body, behind the inner walls. You can’t see it without opening the microwave. But if you’ve checked everything else — and it’s still sparking or smelling burnt — the magnetron might be the problem.

Some signs of a bad magnetron include:

• Food not heating properly
• Loud buzzing or clicking noises
• Sparks with no metal inside
• Burning smell even with an empty microwave

I had this problem last year. I cleaned everything, changed the waveguide cover, but nothing worked. A repair person came and confirmed the magnetron was burnt out. I had to buy a new microwave because fixing it cost more than a new one.

This is not something you should try to fix by yourself. It’s dangerous and has high-voltage parts. Call a technician or take it to a repair shop.

• Poor heating or no heating
• Strange sounds from inside
• Sparking without any metal
• Burning smell continues after cleaning
• Call a professional if you suspect magnetron damage

Know When It’s Time to Replace Your Microwave

Sometimes, the best thing you can do is say goodbye to your old microwave. If you’ve tried cleaning, checking all parts, and even got it repaired — but the sparking or burning smell still comes back — then it may be time for a new one.

Microwaves usually last about 7 to 10 years. If yours is older than that, many parts may start to fail one by one. The cost of fixing all those parts could be more than buying a new one.

Also, if your microwave is heating unevenly, making strange noises, and giving off smoke or sparks — it’s not safe to keep using it. I once kept using an old one that sparked often. One day, it shut down completely while making a loud pop. That’s when I realized it could have been a fire hazard.

Buying a new microwave may seem expensive, but your safety is more important. New models are safer, more energy-efficient, and work better.

• Microwave is more than 10 years old
• Sparks keep happening even after cleaning
• Food doesn’t heat right
• Repairs cost too much
• Smell or smoke keeps returning

Final Thoughts

Microwaves are a big help in every kitchen, but when they start sparking or smelling like something is burning, you need to act fast. From checking for metal to replacing broken parts, every step matters. Don’t ignore small signs. It’s better to clean, check, and fix it now than face bigger problems later. Safety always comes first.

Frequently Asked Questions (FAQs)

Is it safe to use a microwave after it sparked?

No, it’s not safe to keep using your microwave after it sparks. Even if the spark stops, something inside may still be damaged. The spark could have come from metal, burnt food, or a broken part like the waveguide cover. You should unplug the microwave and check it before using it again. Always fix the cause of the spark first.

Can grease cause a microwave to smell burnt?

Yes, grease can easily cause a burnt smell in your microwave. Grease builds up over time on the walls, ceiling, and parts like the waveguide cover. When you use the microwave again, the grease heats up, smokes, and sometimes even catches fire. Cleaning regularly with warm water or vinegar helps stop this from happening.

Do I need to replace my microwave if it sparks?

Not always. First, check for metal, food debris, or damage inside. Sometimes cleaning or replacing one small part like the waveguide cover can stop the sparks. But if the problem keeps happening, and the microwave is old, then yes — it may be time to replace it. Always put safety first.

Is it okay to put foil in the microwave?

No, it’s not safe to put aluminum foil in the microwave. Foil reflects the microwave energy and causes sparks. Even small pieces can make the oven flash or burn inside. Some frozen meals may come with special microwave-safe materials, but it’s always best to remove foil unless the label clearly says it’s safe.

Can a microwave catch fire?

Yes, if sparks or smoke are ignored, a microwave can catch fire. Grease, food spills, or metal objects inside can cause flames. If you see sparks or smell smoke, turn it off right away and unplug it. Never leave a microwave running alone. Keep it clean and check it often to prevent fire risks.

Do I need a technician to fix a sparking microwave?

Sometimes yes, especially if the problem is inside the parts you can’t reach, like the magnetron. But if it’s just dirt or a broken cover, you can try fixing it yourself. If you’re unsure or see signs of deeper damage, calling a professional is the safest choice.

Is it normal for old microwaves to smell burnt?

No, it’s not normal. A burnt smell means something is wrong. Old microwaves can have worn-out parts, burnt wires, or leftover food inside. If the smell happens often, and cleaning doesn’t fix it, it could mean the microwave is breaking down. You may need to replace it.

Can I clean a waveguide cover?

Yes, you can clean it gently if it’s just dirty. But be careful — it’s very delicate. If it looks burnt or has holes, you should not clean it. Replace it instead. Never scrub hard or use harsh cleaners. And always unplug the microwave before cleaning this part.