A corroded microwave should not be used. You wouldn't consume food from a rusted can since it's unsafe. Microwave radiation causes no danger to people as long as the interior of the microwave oven stays sealed and undamaged; you may sand and restore its interior using microwave paint. Rust inside the oven indicates that moisture may have penetrated the unit and caused corrosion to other internal parts.
However, this does not mean that you should throw out your old or damaged microwave. Instead, call a professional repair service immediately so that the device can be restored properly.
Cleaning and Preventing Rust in Microwaves After using a microwave oven, clean the interior with a moist hot towel. This is one of the most fundamental microwave maintenance hints. Food and grease can solidify the residue and cause corrosion if the interior of the microwave is not cleaned. Corrosion can also be caused by water that has penetrated the metal body of the oven.
Corrosion is an adverse reaction by which metallic elements are dissolved into other substances. In this case, iron reacts with sodium to form salts that deposit on the inside of the microwave. Iron deposits are brown while salt deposits are white. If you see iron stains on your microwave shell or salt stains on any other part of the oven, there is corrosion present. Corrosion is never good for the performance of the microwave, so it's important to take care of this problem before it gets worse.
There are two types of rust: acid-based rust and alkali-based rust. Acid-based rust results from exposure to acidic foods or liquids at a high temperature. Examples of acidic foods include tomatoes, grapefruit, and orange juice. Liquids that are acidic such as tomato sauce or vinegar can also cause rust. Alkaline-based rust results from exposure to alkaline foods or liquids at a high temperature. Examples of alkaline foods include potatoes and noodles. Milk and eggs are common sources of alkalinity.
It should be fine as long as the microwave appears to be working correctly. I've unintentionally left cutlery in the microwave before and the device was not harmed. Damage is only a potential, not a foregone conclusion. Some metals can even be microwaved; the nature and form of the metal determines this. For example, aluminum becomes an annealed color when heated in the microwave and will likely withstand multiple cycles of heating and cooling without damage. On the other hand, silverware made from stainless steel may develop a blackened film on their surface if placed in the microwave.
The main safety concern with any household appliance is electricity. Electricity is dangerous if you get your hands on it, so you have to be careful not to touch any wires or plates while working with a microwave. If anything feels warm, then there's probably a problem that needs addressing immediately before you could be hurt. A microwave oven is an expensive piece of equipment to break, so call a technician immediately if you see any signs of trouble.
As long as you follow proper safety procedures, using a microwave is no more dangerous than another common household appliance such as a stove or dishwasher. However, if you're not careful, you could cause serious damage to yourself or your property when cooking in a microwave. Be sure to use appropriate protective measures to avoid harm to your food or yourself.