On Wed, 27 Feb 2013 10:07:44 -0800, Red wrote:

about 25 there were 6 that had an off white coating similar to mold.
The coated knobs were identical and appeared to come off the same
piece of old test equipment. The rest of the knobs were perfectly
normal. Thinking they were moldy I soaked them overnight in a clorox
solution and it didn't phase them. So it definitely wasn't mold. But
with soapy water and a old toothbrush they cleaned easily so I
determined it was an old plastic compound reaction.

That's exactly my experience.
http://www5.picturepush.com/photo/a/...g/12297573.jpg

The plastic on the handles was coated with a thin white layer
which I could scrape off with a sharp tool (the results in
that picture are of a screwdriver scraped years ago, but some
of the persistent white stuff is still on the handle, in spots).

I don't know WHAT it is!

Like you experienced, it wouldn't 'wash' off and chlorine bleach
didn't faze it (of course, if it 'is' mold, it would be dead but
still there if bleach did kill it, since it's white).

I don't know if it's a "mold" or a "chemical".
It does seem to 'infect' other tools - but both a mold and a chemical
'can' do that (think hydrochloric acid).