Microwave Cavity bottom rusting
After many years of use, a microwave may start to show some wear and tear just like any other kitchen appliance. One common issue with microwaves is that the interior paint will begin to peel off over time. Since peeling paint can both become a fire hazard and contaminate food you cook in the unit, it's important to prevent and repair the interior paint when it peels.
When food splatters onto the interior of a microwave and it isn't cleaned off right away, it can bake onto the surface of the microwave interior and harden, creating a "hot spot." These hot spots get warmer than the rest of the microwave's interior during the cooking process, which can lead to the deterioration of the paint in that area of the microwave. Sharp utensils may also scratch the paint off the walls.
Aside from causing the flaking of the interior paint of the microwave, hot spots that form in a microwave can create other issues. The spots where food baked onto the surface or where the interior paint was scratched by a utensil might spark when the microwave is turned on. If paint is peeling and hanging it creates a possible fire hazard. To prevent this sparking, the interior of the microwave must be smooth and clean.
Prevention is the best course of action when it comes to peeling paint on the inside of a microwave. You can stop peeling paint before it starts by always cleaning up spills or splatters from the inside of the microwave as soon as they occur. Once peeling begins, though, use fine-grit sandpaper to remove the hanging pieces of paint from the microwave's interior to prevent further peeling.
The microwave is safe to use only if the peeing is minor, although the scratched areas may rust over time if not repainted. If there is excessive peeling of several large areas of the microwave and rusting everywhere, it's best to just buy a new microwave.
To fully repair a microwave with peeling paint, you must remove the peeling paint before repainting the microwave so that it doesn't rust. Unplug the microwave from the wall so there's no power going in. Then clean the inside to remove flaked away paint, grime, or any grease. Then wipe down the inside with a dry cloth or paper towel and then gently sand down a few of the peeling areas.
Once everything is prepared, the inside of the microwave can be pained. Microwave safe paint is found in all kinds of appliance stores. Be sure that to ask a store employee if you can't find the right paint. It may be easier to buy the spray paint version of appliance paint, but as long as it's made for appliances and is microwave safe, then it should work.
Test the paint in a small area first. Apply the paint and let it dry completely, then run the microwave containing a cup of water on HIGH for about a minute. The painted area should not be any warmer to the touch than the rest of the oven after you remove the water. After painting, allow the microwave to dry for at least 24 hours in a ventilated area before using.