What Causes and How to Fix Rust in a Microwave

Microwaves are the most convenient way to get a hot meal or snack. They are undoubtedly one of the essential appliances in any condition, and they generally work without fail. Unfortunately, like most things with metal, they can start to rust over time. So, how do you deal with this?

The rust in a microwave is caused by food splatters and spills left uncleaned in the microwave, which eventually hardens, resulting in a rusted interior paint. However, small patches of rust can be patched up by replacing the eroded paint that covers the metal underneath.

This article will be going over what causes rust in a microwave, how to prevent rust, and remove it. We will also discuss when you should replace the microwave entirely. So continue reading if you would like to learn more.

Fixing rust in a microwave.

What’s the Problem With Rusted Microwaves?

Besides the fact that a rusted microwave is visually unappealing, it is also a danger to your health and home. A microwave is essentially a chamber of electromagnetic radion that cooks food very quickly, and they do not play well with metal at all. 

If you have ever put aluminum foil in a microwave, you’ll quickly learn how bad of an idea that was when you see large sparks and an audible pop. This is because metal heats up incredibly fast. And since aluminum foil is so thin, the electric fields that microwaves produce cause electricity to travel through metal, causing the metal heat up and spark or even catch on fire. 

This same effect can happen to a rusted microwave because the metal underneath the paint is now exposed. This is one of the reasons why rusted microwaves are so dangerous and are a genuine fire hazard. 

The other reason is that radiation leakage can occur. Microwaves use Radiofrequency (RF) radiation to heat food, which is safe until radiation leakage occurs. Radiation affects biological cell processes and is ultimately dangerous to your health. 

In many cases, you should simply toss a microwave if it is rusted – it isn’t a normal occurrence and is generally not worth the risk if there are significant rust patches. But in a lot of other cases, you can repair it. 

What Causes Rust in a Microwave?

The interior of a microwave is metal covered by paint. The paint acts as a shield for the metal and helps prevent the above examples when it gets directly exposed to the RF radiation.

This paint can end up peeling if food splatters in the microwave and is left to set and harden. This is one of the reasons why it is very important to clean up any spills immediately. This snowball effect from a dirty microwave can end up being dangerous and ultimately should be avoided at all costs if possible. 

How to Fix Small Patches of Rust in a Microwave

Now that we understand how rust generally occurs in a microwave, we can get into how to fix small amounts of damage. 

Gather Your Supplies

Before you get started, you’ll need the following supplies to remove the peeling paint and repair the rusted areas in your microwave:

  • Rubber Gloves
  • Do-It-Yourself (DIY) cleaning solution containing one part trisodium phosphate and ten parts water
  • A clean, wet cloth 
  • Wire brush or knife
  • Sandpaper
  • Rubbing alcohol
  • Painter’s tape
  • Protective mask
  • Microwave-safe spray paint

Remove the Rust and Paint Over It

Make sure the microwave is unplugged before you start to clean or repair it and that you are wearing a pair of rubber gloves. Follow the steps below:

Remove the Rust

  1. Clean the rusted area using the DIY cleaning solution and rinse it with a wet cloth. 
  2. Scrape off the peeling/flaking paint using the knife or wire brush. Damaged paint must be removed because it can affect the new paint – plus, it will make it pretty much impossible to properly apply a fresh coating of paint if the surface is uneven.
  3. Once that the old paint is removed, use sandpaper to sand the rusted area. This will make the surface even and smooth. 
  4. Clean the leftover debris with rubbing alcohol.

Paint Over Rusted Areas

  1. Cover areas you don’t need to paint with painter’s tape.
  2. While wearing a protective mask, spray a coat of paint onto the rusted area. If you need to add another layer of paint, repeat the painting process.

We hope you weren’t planning on microwaving anything because it can take up to 12 hours for the paint to dry.

Note that it is generally safe to clean and repaint the rust if it has happened below the turntable but you should consider replacing the microwave if you have rust on the sides or the ceiling. It is also recommended to replace a severely rusted microwave as it is dangerous due to radiation leakage and sparking due to exposed metal.

Tips For Cleaning a Microwave

The best way to prevent rust from occurring is to clean your microwave and regularly wipe up any spills. 

A simple solution that you can make is with just baking soda and water. Simply combine one part baking soda and one part water to loosen up harden spills – remember, rust often develops because hardened food starts to crack the paint, so it is essential to thoroughly clean up any left behind messes. 

If you also have a foul odor coming from the microwave’s interior, you can mix one tablespoon of white vinegar and a bowl of water and then microwave the bowl for 5 minutes to help get rid of the smell. 

The steam will not only help with the smell, but it will loosen up hardened food for easy cleaning. 

For a deep clean, soak the turntable in hot soapy water while giving the microwave a thorough clean with a no fume commercial cleaner such as this Fuller Brush Microwave Oven Cleaner. We recommend doing this at least twice a year, even if you are neat with your heating. 

Consider a High-Quality Microwave As Replacement

Microwaves that you can buy for $60 are fine, and they work, but they’ll have average build quality at best and not to mention they are generally only 600-700 watts (which means your food will take longer to heat up compared to the frozen food standard of 1100-1200 watts).

If you’ve ever heard the saying “buy once, cry once,” this applies to microwaves very well. You are likely to use it very often every day, meaning that it holds a lot of value from a practical standpoint.

Here is a useful guide on how to choose a microwave:

We recommend a couple of microwaves above the cheaper options but aren’t crazy high in price (and there is an argument to be had if buying an expensive microwave is worth it anyway). 

Toshiba EM131A5C-BS

This microwave is one of the best selling ones on Amazon, and for a good reason. It incorporates the things most people care about: power, easy to clean, and quality of life features such as a temperature sensor and the ability to turn sound off. 

It is currently going for $120 as of writing this, which puts it in the middle of the pack as far as microwave pricing is concerned. That money gets you an overall great microwave that is easy to recommend for most people. It’s not just good for the price, but it is one of the best on the market in general.

Farberware Black FMO12AHTBSG 

This is another great option for a lot of people. Like the Toshiba, this has the amount of power needed to heat and cook food efficiently, and with the added “grill” functionality, you’ll be able to get char on hot dogs, for example, without whipping out the outdoor grill.

One downside is that it is quite heavy and large like the above. The price is around that of Toshiba, making it a tough decision regarding which one is superior. We will call it a tie since, even though the Farberware is missing out on some useful features, we think there are folks who will appreciate the grilling feature.

Toshiba EM925A5A-BS

Toshiba makes the list again – they make great microwaves! This one is for people who need something smaller but don’t want to sacrifice too much power or spend over $100. It offers useful features such as a sound off option, and with 900w of power, it provides a good compromise between size and wattage.

At the time of writing, it will cost you $90, making it overall a good value for what is being offered. 


Rust in a microwave is dangerous due to it being a fire hazard and potentially leaking radiation. However, depending on the severity of said rust, you should repair the damage within 24 hours. 

To help prevent rust in the first place, ensure you are cleaning up any spills as those can harden damage the paint that is covering the metal underneath. We also suggest giving your microwave a deep clean at least twice a year, even if it doesn’t appear dirty.

If you have to throw out your current microwave, we recommend springing for one that is using quality materials and is easy to clean. It is better to buy one microwave for $120 and have it last for years rather than a $50 one that you might have to replace 2-3 times. 

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