The granddaddy of all modern plastics is vulcanized fiber, still made
by NVF (formerly National Vulcanized Fibre) company. It's made by
pickling paper, and you can see the process on the NVF web site.
Vulcanized fibre was a large commercial product long before bakelite
came on the scene. It still is used for printed circuit boards and
some other applications. At one time it was used extensively to make
luggage and cases for fragile instruments.

As for the coat hangers, read Noel Hume's Historical Archaeology. He
recounts that the coat-hanger dowsing method is used by cemeteries to
identify occupied gravesites. I have used it successfully, and
recently filed a report with DelDOT on a site where I used it. We
defined a disturbance that turned out to be the drainfield of a
former trailer park.

I not only used the technique, but had the nerve to report it. It
works for some people, and not for others.

Soon after INH published  the method, back in the dark ages, the
occupant of a neighboring office asked me if there was a way to find
a pocket watch he had dropped in his garden. Surely, I said. I bend
coat hangers and put them in soda bottles as specified in the Noel
Hume book. It was a large steel framed building, so I did not expect
to see results in my office. But when I walked by the old 914 Xerox,
the coat hangers went wild. Clearly they were attracted by the rather
massive magnetic field of the copier.

He found the watch.
--
Ned @ Heite.org

You know you're in trouble
when your idea of excitement
is the way the receipt pops
jauntily, even with gay abandon,
from the slot in the ATM machine.