Microwaves have limited lifespan

Q: I have a microwave that has rust in the inside corners. I would like to know if I can paint over the rust. Do I need a special type of paint? — Matt M., East Stroudsberg, Pa.

A: One of the important things to know about microwave ovens is that, while they are very convenient and very safe to use when in good condition, once they begin to age, they can become not so safe to use. When a microwave oven’s door seals begin to break down or rust is seen in the cooking area (the inside compartment), the unit should not be used at all.

In the case of interior rust, microwave “leakage” is not really a concern (unless the rust is extreme and compromises the metal box that comprises the cooking area), but electrical arcing is a potential problem.

Have you ever accidentally put something containing metal into the microwave and been frightened by the loud popping, sparks and burning odor that immediately start up? Rusty, exposed spots can do that as well, usually to a smaller extent, and you just don’t want stray electrical arcs inside any electric appliance.

Many eons ago, when dinosaurs roamed the Earth and I was just a wee lass, microwave ovens were big and expensive and didn’t even have digital clocks. Taking them in for repairs back then made sense: They weren’t just a small appliance, they were an investment. Today, small- to medium-size microwave ovens sell for as little as $50 and are very energy efficient.

I recommend that you assess the amount of use the oven actually gets. Do you cook whole turkey dinners in it, or just use it to reheat plates and make popcorn? If it’s the latter, a smaller, inexpensive unit will serve. In the meantime, dispose of the old microwave according to your local municipality’s guidelines — these can be checked by calling the city or county directly, or visiting its Web site.