Rust Inside Microwave: Causes, Fixes, and Prevention Tips

Paradise Appliance
January 3, 2024
Microwave Repair

Since the interior of most microwaves is made of metal, rusting is an issue that can sometimes occur. Rust inside a microwave, especially when left untreated, can be a potential health and safety hazard and may damage your appliance to the point where it needs replacing.

This article explains why rust inside a microwave occurs and could be unsafe. It also covers how to fix it and prevent it from happening again.

Why Rust Forms Inside a Microwave

The inside cavity of a microwave usually has a special coating of microwave-safe paint that protects the metal from rusting. 

However, when this protective coating is cracked, chipped, worn down, or damaged in some way, it can expose the metal underneath, allowing oxygen and moisture to come into contact with it, causing rusting.

While some microwaves have paint that is more prone to chipping than others, common factors that can contribute to its deterioration and rust forming include:

  • Age: The general wear and tear that occurs over the years means older microwaves are more susceptible to rust.
  • Harsh Cleaning Methods: Using strong chemicals and abrasive materials to clean and scrub your microwave can wear down the interior coating.
  • Lack of Cleaning: Food spills can be corrosive if not cleaned immediately, as the acid from some foods can damage the interior coating.
  • Moisture Buildup: If a microwave has blocked vents or is not dried after being cleaned or used, moisture can build up and lead to rusting.

Why a Rusty Microwave Interior Can Be Hazardous

A small amount of rust inside a microwave isn’t going to cause any serious harm if it is spotted right away and dealt with. However, if rust is left long enough, it can compromise the microwave’s internal structure, and although the risk is low, it could potentially allow some radiation to leak out while it’s in use. 

Also, the longer you leave rust, the less likely you’ll be able to fix the issue, meaning you’ll have to buy a new replacement. Once rust gets to the point where holes in the metal have formed, no matter how small they are, it’s already too late, and your only option would be to replace the microwave.

There’s also the potential issue of food contamination, as particles of rust and microwave paint may flake off and land in your food. Rust inside a microwave can also impact its functionality, meaning it doesn’t heat food evenly and, in some cases, may even damage electrical components, leading to safety issues or the appliance’s breakdown.

How to Remove Rust from Inside Your Microwave

If your microwave interior just has a small amount of surface rust, you may be able to fix the issue yourself. Here are the steps for doing so:

  1. Unplug the microwave for safety.
  2. Remove the turntable from inside.
  3. Clean the inside of your microwave with a paste made from baking soda and water and a cloth or kitchen sponge to scrub it.
  4. Then, clean again with a white vinegar and water mix or dish soap.
  5. Dry the inside of your microwave thoroughly with kitchen towels or a dry cloth.
  6. Gently sand down the rusted areas with fine-grit sandpaper until all the rust is removed, leaving a smooth surface.
  7. Clean away any dust from the sanding and ensure the area is dry.
  8. Tape over areas that don’t need painting, and cover the vents.
  9. Use a special-purpose microwave cavity paint to paint the sanded areas of exposed metal, following the manufacturer’s instructions on the tin. Do not attempt to use any other type of paint, as this could be dangerous.
  10. Allow the paint to dry and cure fully before using the microwave again. This may take between 24 and 72 hours.

How to Prevent Rust from Occurring

Okay, now you know why rust can form inside a microwave, why it is potentially hazardous, and how to fix it if it isn’t extensive; the next step is to prevent it from occurring again.

Here are some top tips for preventing rust from forming inside your microwave:

  • Clean your microwave regularly, using gentle means like a soft cloth and dish soap. Avoid harsh detergents and abrasive scrubbing pads.
  • Cover your food while microwaving to avoid spits and splatters on the cavity walls.
  • Clean up food spills in the microwave promptly. Do not let them sit.
  • Do not use metal utensils that could scratch or damage the cavity paint.
  • Do not let moisture sit inside the microwave. Dry it with a towel after every use and cleaning.
  • Take out the turntable and clean it separately. Allow it to dry fully before placing it back inside.
  • Inspect your microwave regularly, and fix any cavity paint chips promptly if they occur.


Rust inside a microwave is one of those issues that must be tackled quickly to resolve. If left, rust only tends to worsen, compromising your microwave’s functionality and safety.

For some, the steps involved with fixing rust inside a microwave, such as sanding and painting the affected areas, might be too much effort, and they would prefer to replace the unit entirely. However, for those who are more DIY-savvy, it can be a challenge worth taking on.

Overall, the best thing to do regarding rust inside a microwave is to take steps to prevent it from happening in the first place. This way, you don’t have to deal with the hassle and expense that comes along with it.


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