Why Do Microwave Ovens Rust Inside? How To Prevent & Remove It?

Image of a microwave oven that is not rusted from inside

Microwave ovens are handy kitchen appliances that make food preparation and cooking easy. However, like all other electric appliances, they are affected by various problems, like rust on the inside. Let us find out what causes this issue and whether it can be fixed. Why do microwave ovens rust inside?

Rust forms on the inside of a microwave oven due to the age of the oven and environmental factors like humidity. It is also caused if liquid gets spilled inside the oven, and it is not cleaned properly with a dry cloth. Rust that forms inside a microwave oven can cause safety and health risks.

Let’s now talk about microwave oven rust in detail.

How Does Rust Form On Microwave Oven Surfaces?

Rust forms when a metallic surface comes in touch with air and moisture. The oxygen in the air causes the exposed metal surface to oxidize and produce a layer of rust.

Rust damages the look of electrical appliances like microwave ovens. But more importantly, it impacts the efficiency and quality of the device. Rust can impede the operation and cause the device to display erratic behavior. The presence of rust can also trigger hazardous sparks and fires and lead to accidents.

Although rust on any surface of a microwave oven deserves attention, it is more dangerous when rust is inside the oven. You can get away with ignoring rust on the outside of an oven for a while. However, you should never overlook rust on an inside surface. The presence of rust on the outside of an oven does not cause serious safety concerns unless it eats its way into the interior. It can also be fixed easily.

However, rust inside an oven makes the device unsafe for food preparation. It can spread quickly and render the device unsafe for use. Rust on the inside is more difficult to fix. If you ignore it for too long, rust can even damage the device beyond repair.

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Why Is Rust Inside A Microwave Oven Dangerous?

Microwave ovens cook food using microwave radiations. These waves cause food particles to vibrate quickly and generate heat. The heat thus produced cooks the food.

Microwaves bounce off the inside surfaces and containers placed inside an oven. When these surfaces have rust, microwave radiations can cause health and safety hazards in the following ways.

Arcing And Flying Sparks

Microwave rays can cause sparks when they bounce off uneven metallic surfaces. When the inside of a microwave oven becomes rusted, bare metal is exposed. When microwaves bounce off this surface, it results in sparks, and arcing can cause a fire to break out.

Microwave Radiation Leakage

The inside surfaces of the microwave oven are also prone to rust. When these surfaces become rusted, the integrity of the appliance is compromised. Rust on the doors of the microwave oven can cause radiation to leak out. It is very dangerous as exposure to microwaves can cause physical damages.

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How To Prevent Rust Formation Inside A Microwave?

As microwave ovens age, they are prone to physical damages. Exposure to the environment can cause the paint on the insides of the appliance to peel.

You can keep your microwave in good working condition with regular cleaning and maintenance. Clean the insides of the microwave with a damp rag after each use. Mop up any spills promptly to remove it quickly and easily.

If you let spilled food settle, it will harden on the surface. Each time you use the microwave, this leftover food will crisp up and form a thick layer. It will be difficult to remove it later. Over time, the residue will lead to rusting inside the oven.

To prevent rusting from food residue, tackle stains and spillage with the following steps:

  • Place a container with water and a lemon slice inside the microwave oven.
  • Run the oven in a low-temperature setting and let the water evaporate.
  • Gently coax the residue off with a damp cloth.
  • Do not use any harsh cleaning solution or abrasive material for cleaning the inside of the oven.

When cleaning the oven, take care to avoid scratching the paint from the surface and exposing bare metal.

How To Remove Rust From The Inside Of A Microwave Oven?

Not all paints are suitable for the insides of a microwave oven. Only specially formulated microwave paints can withstand the high temperature inside the cavity. Other regular paints will peel off within a few days of application.

The inner container of the microwave oven is metallic. Special paints are applied on top of this base cavity to seal it and keep it intact.

When part of the paint peels off, the metallic surface becomes exposed. It develops rust when exposed to moisture from food, accidental liquid spills, or even environmental elements. Rust can quickly grow and affect larger areas of the cavity. It can also cause safety and fire hazards.

So, you should examine any rust inside the microwave oven properly and restore it. If you notice any chipping of paint, you must promptly repaint the interior surface to avoid further damage. But before repainting it, you must get rid of the existing rust.

Gently scrape off the flaking paint with a scraper or metal brush. Sand the rusted area to get rid of the rust stains completely. Then wipe it down to make the surface smooth. Finally, paint the cavity with multiple layers of recommended microwave paint. Allow it to dry between coats and let the paint dry up completely before using the equipment again.

Get in touch with the authorized service personnel to tackle the removal of rust and repainting if you do not have experience in this area. Avoid using the microwave till you fix the problem, as continued use will put you at greater risk of an accident.

Never wait till the rusted area develops small holes. If any of the rust spots develop small pinholes, it indicates extensive damage. At this stage, the microwave oven is beyond repair. You will have to get rid of the appliance as it is no longer safe to use.

You should also consider replacing your microwave oven if the coating is actively flaking or the paint peels inside the cavity.

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Signs That It Is Time To Replace Your Microwave Oven

When you use a device carefully, it will work for much longer. Nonetheless, there comes a time in the life of every electrical appliance when it is no longer safe for use. You will observe red flags that signal it is time to replace your microwave oven.

Look out for the following signs that suggest it is no longer safe for use:

  • New sounds and smells that signal a problem.
  • If the food does not cook properly and burns or remains undercooked, it indicates that the efficiency of the device has deteriorated.
  • When the door does not seal completely, it means that the microwave oven is faulty and prone to leak radiation.
  • The buttons and keypad do not function properly when the device is too old or damaged.

Most microwave ovens have a lifespan of seven to ten years. With regular cleaning and maintenance, it will not need any big repairs. Take good care of this appliance and attend to any problem areas like rusting on the inside, and your microwave oven will serve you for longer.