Why do microwave ovens rust? Causes and how to avoid it!

It is true that microwaves are handy and convenient appliances in every kitchen. They make cooking easy and convenient.

But, like other metals, the metal surface in the microwave oven can get rusted. 

Now, let’s discuss the reasons which cause rusting.

A microwave oven may rust for a variety of reasons. The first reason is of course the passage of time like everything else with time metal surfaces tend to rust. Natural factors like humidity can also cause microwaves to rust over time. Moreover, oftentimes while using microwave ovens, liquids get spilled inside them which, if not properly cleaned, can cause rusting.

Rust forms when the surface of metal comes in contact with air and moisture. It can negatively affect the performance and effectiveness of the appliance.

Keep on reading to learn more about rusting inside the microwave.

Is it safe to use a rusty microwave?

If you are still here it means you are interested to know about- Is a microwave safe to use if rusty inside?

No, it is not recommended to use a rusty microwave. While rust on the exterior of the microwave oven doesn’t pose a big threat, rust on the interior surface of the microwave oven can cause major problems.

I mean you wouldn’t want any rust particles to get in your food right!

Like other appliances, the microwave oven will wear thin after years of usage. Over time, the paint in the interior of the microwave oven will start crumbling.

After which it can come in contact with oxygen to form rust. The rust will slowly weaken the metal surface and eventually break it.

If the inside of the microwave oven isn’t cleaned properly, the food particles piled up in it will result in rusting. 

Sometimes the rust on the surface isn’t visible because it is covered with food stains. Make sure to wipe the inner surface with a cloth while keeping the microwave unplugged.

Issues with using a rusted microwave

There are two serious hazards that can be caused by rusting of the interior of the microwave oven.

1. Arcing or rust arcing

Arcing happens when the rays present inside the microwave bounce against the metal surface inside, it will cause sparks while using the microwave. Sparks can occur because the metal coating inside is corroded by rust. 

When the sparks appear quickly turn off the microwave and disconnect it from the socket. 

2. Microwave radiation leakage

Rust inside or on the door of the microwave can result in radiation leakage. It is highly unsafe and poses a serious threat. Large amounts of radiation can adversely affect human health.

The radiation takes a long time to show its negative effects but it is best to replace the microwave oven as soon as possible.

How is rust formed inside the microwave oven?

Rust is a reddish-brown substance that is formed by the actions of air and water. The process of oxidation has a part to play as the oxygen gets trapped inside the microwave oven. Metals can get rusted by coming in contact with air and water.

Likewise, when the metallic surface of the microwave oven comes in contact with air and moisture, it forms rust.

Even the food spilled while using the microwave oven, if not cleaned, can cause corrosion. The food stains which are left uncleaned can form a thick layer and make a breeding ground for bacteria too.

Rusting can hamper the overall functioning of the device. It can deteriorate the condition of the microwave as rust will keep growing until something is done about it.

Other than oxidation and food spillage, factors like humidity play a role in causing the surface to rust. In humid temperatures, the metal corrodes at a very fast rate.

The rust will start spreading fast to other areas and eventually it will obstruct the proper functioning of the microwave. It can expose the parts of the microwave which can cause fires and lead to serious accidents.

Due to corrosion, the paint starts chipping off on the outside and results in an unappealing appearance of the microwave oven.

How to remove rust from a microwave?

As we know using a rusted microwave is highly problematic, so let’s talk about removing rust from the microwave oven. 

  1. First, remember to unplug the microwave. It should not be connected to the power socket even if it is turned off.
  2. Now, examine the microwave properly to see the rusted areas clearly. You can flip it until you clearly see the rusted section.
  3. Now, clean the affected area with a damp cloth to remove all the waste accumulated on it. Sometimes the rust isn’t visible as it is hidden by the hardened food stains. So make sure to clean it properly.
  4. Once the rusted areas are visible, use rust removing agents or soaps. These are easily available in markets. They will remove the rust gently and effectively giving you a smooth and clean surface.
  5. If the rust is stubborn, it can take some time to remove it. Leave these agents or soaps for 10 to 15 minutes. You can repeat this process if needed.

After removing all the rust from the interior, clean the entire interior of the microwave oven with a mixture of baking soda and dishwashing liquid.

For removing extreme hard rust from surfaces AZ rust recommends using sandpaper.

This will ensure deep cleaning of the interior of the microwave leaving no debris.

Once thoroughly cleaned, you can cover any exposed areas with microwave-safe paint to ensure it looks good.

Over time, the paint on the outer walls of the microwave oven can chip off or turn yellow. If the outer part of the microwave oven is rusted, you can remove the rust and give it a lick of paint to make it look as good as new. 

Tips to prevent a microwave from rusting?

Stopping rust from forming up is the wisest thing you can do. In case you are searching for ways how to Stop/Prevent microwaves from rusting then the information below will help you.

Prevention is always better than cure. You can prevent your microwave from rusting by doing the following.

  • After using the microwave, do not close the door immediately. You can trap the moisture inside which will in turn increase the chances of rusting. It is advisable to keep the door open for a few minutes to let the moisture escape. 
  • Always dry the corners of the microwave completely.Take a cloth and dry it out. Leave it open for sometime to let it dry on its own. Make sure it is free from any dampness.
  • Another thing to always keep in mind is to avoid any spilling of food or liquid inside the microwave. If you do not clean the spilled food properly, it will harden after every use of the microwave. Consequently, it will get difficult to remove it. 
  • To clean and remove the spillage and stains, keep a container filled with water and a lemon slice inside the microwave oven. Start the microwave oven on a low temperature setting and let the water evaporate.
  • Lastly, rub the residue off gently with a clean and damp cloth. 

Even if there is no spillage or food stains in the microwave, you should clean your microwave regularly to ensure its efficiency and quality of it.

Regular cleaning of the interior of the microwave will protect the quality of food cooked.

While painting the microwave oven, use only microwave-safe paints and do it carefully. Paint it only after a thorough cleaning.

As mentioned earlier, radiation leakage from microwave ovens can lead to severe issues. So if you notice any rusty surface, check for radiation leakage and get your microwave repaired or replaced. 


In a nutshell, to conclude you can say using a rusty microwave oven is not a good idea at all and can cause serious problems.

Taking proper care and regular maintenance can keep your microwave in good condition for years. Use anti-rust products but only trusted solutions. Clean your microwave thoroughly.

Rusting of the microwave can cause arcing and radiation leakage. So proper care and cleaning of the appliance is necessary.


Dangers of Rusted Microwaves: hunker.com