"Trail Rider" wrote in message
...
Microwave oven was arcing, so after reading the repair faq I learned
that the wave guide cover was a possible source. Sure enough the cover
had food material on it that had carbonized. I tried soap and water
but that wasn't removing it. I was able to scrape some of it off using
my finger nail but there was still material that didn't want to come
off the cover. So then I tried a scotch brite scrubbing sponge and
gave it a good scrub. That did the trick and the microwave now works.
However, during the cleaning I noticed that a shiny material was being
removed from the guide in addition to the carbonized food particles.
I'm guessing this was the material the waveguide is made from which
appears to be mica. Are these small flakes toxic or otherwise
dangerous to health?


Particles of mica dispersed by arcing could possibly be hazardous -
especially showered onto your dinner.

I certainly wouldn't risk it.

Whether you chose to follow suit is up to you, but in this situation I would
remove the mica 'window' and throw it in the bin. The risk you would be
taking is that certain foods pop or spit and particles could end up in the
waveguide, usually this isn't a big problem unless you explode an egg in the
microwave. When I did that a large chunk of egg white blocked the waveguide
and overloaded the transformer.

Its also possible you might be able to locate a component supplier for
consumer goods and order a new mica - but I'm guessing its pretty old as
most use dielectric plastic these days.