Why do microwave ovens rust inside?

Rust in microwave? Metal cavities, by their very nature, start to corrode when in contact with oxygen in air.

So, yes! Metal cavities inside microwaves are also prone to corrosion and thereby rust.

However, when do microwave ovens rust? Why do they rust?

In this post, we’ll answer all such queries & questions of you!

Why do microwave ovens rust inside

What causes a microwave to rust inside?

Rust in microwave? Well, microwave ovens rust inside because of 4 factors. They are environmental aids, foodstuff spills inside ovens, humidity, and the age of the microwave.

Speaking in general, a microwave’s cavity is made with metal. The internal metal walls are painted so radiation effects are optimal. Whenever the microwave-safe paint peels off, the metal rust risks increase.

As your microwave ages, the more it is prone to rust. The reason being it is used more, has been exposed to the environment more, and similar. In case the paint coating is removed accidentally, the insides are exposed to humidity. When the metal walls react with oxygen present in the air, it then slowly begins to rust.

Also, not cleaning microwaves neatly can cause them to rust. Oxygen is present in foodstuffs as well. When these foodstuffs stick to the cavity wall or bottom, it reacts with metal whilst peeling off the paint. The oxidation occurs and thereby rusty layers. It then weakens the metal making it vulnerable to radiation. In turn, it causes sparks or sometimes, fire.

Remember ! : Internal rusts are a worrisome factor! External rusts are also not good. These external rusts when they make pinholes to the internal cavity become most-worrisome!

Why is the bottom of my oven rusting?

Why is the bottom of my oven rusting

Well, check if you’re accidentally spilling off liquid or foodstuff below the turntable. It could happen while removing the cuisine out of the microwave.

This foodstuff gradually hardens. It sticks much harder to the microwave’s surface. This in turn softens the paint layer, causing it to flake over. Gradually, it causes the bottom to rust!

If that’s the case, wipe off the food splatters after microwaving everytime. Thank us later! It’s still safe to remove rust, repaint the bottom, and reuse the microwave. The arcing risks are lower when rust resides at the bottom as the turntable is above. However, if it’s on the sides, the best is to replace the microwave. The reason being arcing chances are higher when rusts are on sides.

How to get rust off inside of microwave?

How to get rust off inside of microwave

If the microwave rust inside is not widespread, you can take it off! Let’s see how step-by-step:

Assemble all ingredients

  • Fine-grit sandpaper
  • Cleaning solution
  • Scraper
  • Alcohol for rubbing
  • A damp cloth
  • Painter’s tape
  • Rubber gloves
  • Mask
  • Microwave-safe paint

Begin to procedure

  1. Firstly, unplug the microwave! Do not just switch it off, UNPLUG as it’s safer.
  2. Wear rubber gloves
  3. Scrape off the flaking paint
  4. Clean the rusted part with cleaning solution
  5. Sand the rust area. Make it even!
  6. Apply rubbing alcohol over it
  7. With a painter’s tape, tape areas you don’t want to paint.
  8. Wear a mask. Spray microwave-safe paint over the scrubbed area
  9. Let the paint dry fully! After that, apply the next coat of paint.
  10. Once all done, let the paint dry for at least 12 hours. Keep the microwave in a ventilated place for at least 3 days before use.

So, that’s the simple procedure to do!

If there are pinholes or if the microwave is severely rusted, consider buying a new microwave! Otherwise, you risk your microwave to sparking, radiation leakage, and fire. Reveal more about it as you read further this short post.

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How to stop microwave going rusty inside?

Is it possible to avoid microwave rust? Absolutely, Yes! You can avoid rust by taking cleaning care and monitoring. Removing microwave rust inside and outside, both are possible!

Follow these step-by-step:

  1. After cooking, clean up the microwave
  2. After cleaning, never leave moisture inside
  3. Dry the microwave completely before closing every time
  4. When not in use, do not keep a wet container inside microwave
  5. Scrap stubborn foodstuff, mistakenly left out, once in a while
  6. Watch out for any rusting signs frequently
  7. Scrap rust and repaint area, if there is any rust
  8. Service the microwave appliance timely

Follow the above-mentioned rules! You’ll go long with the microwave!

Is it safe to use microwave with rust inside?

Is it safe to use microwave with rust inside

Rust inside microwave? Never use the microwave with rust inside. Not at all! Use only after you remove the rust. It is most-dangerous if the microwave has rust inside.

If it’s an external rust, you still have time! You can take off the rust with a scraper and repaint the area. Also, call a professional expert to remove and repaint rust areas. After which, you can use the microwave as usual. It’s no big deal as such.

If it’s an internal rust, think twice! If the rust is severely spread or has small pinholes, consider replacing the microwave. Buy a new microwave oven if rust is big! You would also be benefiting as you get an extra warranty period. Repairing the big rusty layer is no use as the appliance has already turned poor-in-use. No big warranty period left as well.

On the other hand, if rust is minor on interiors, you’re good to use your good-old microwave after removing it.

In a nutshell, it is unsafe to use microwave with rust inside. It can create arcing, microwave radiation leakage, or fire as well. Also, the rust can contaminate the food. The rust is said to have bad health effects. Let’s brainstorm more on it as you read farther.

Is rust inside a microwave dangerous?

Yeah! The rust inside a microwave is dangerous! It can cause danger in many ways.

Rust arcing

Arcing occurs when microwaves reach bare metal parts inside appliances. Be cautious, when you haven’t put any metal utensil inside and still see sparking, it can be rust arcing. The inner metal layer on walls is exposed to microwaves as paint is peeled. Switch off the microwave immediately as you see the first sign of sparking!

Microwave radiation leakage

The rusted microwave doors or inner walls can cause radiation leakage. As one knows, radiation isn’t good for human health. So, get your microwave repaired or replaced if you found radiation to be leaking out.

To check whether the microwave radiation is leaking or not, take a test! Put your phone inside the microwave. Close the microwave door. Ring a call on your phone. If you can hear the phone ringing inside the microwave, radiations can leak out too.

Cannot rely on just one microwave leakage test! Perform this second-one! Place a fluorescent bulb in front of the microwave. Switch on the rusty microwave. If the bulb flickers or lights, the radiation can come out too.

Be cautious! Repair or Replace the microwave! Do not ignore microwave radiation leakage!


Arcing or sparking is not good! Don’t just ignore the microwave arcing. Turn off the microwave immediately. After that, find a permanent solution immediately.

Constant sparking can lead to fire hazards. Also, the first-time sparks occured for a longer time can create possibility of fire danger.   

Metal food contamination

Microwave radiation has bad effects on human health. It interferes with biological cell processes. Also, it can increase disease risks for leukaemia, sterility, glaucoma, etc. Though chances are rare, you must seek a microwave repair or replacement sooner. Earlier you act, the safer you will be from microwave rust ill-effects!

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Wrapping Up

Rust in microwave? Well, do not worry now as you’ve read this quick post! To conclude, microwave ovens rust when exposed to oxygen! Food splatters, poor cleaning, and humidity are the factors-affecting. Also, old microwaves i.e. 7-10 years beyond are prone to rust.

The good news is that you can repair the rust, if it’s small. If it exists on microwave exteriors, it can also get repaired. Do it Yourself by taking help of this short post or consult with a professional anytime! If rust is big, go for a new microwave. 

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