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Re: Solvents -Reply
The FIRST thing you do is to determine the geochemical and biochemical nature
of both the fossil and the matrix. I get ~40 messages a year from people asking
which acid to use on "fossils." As there is no one fossil or matrix
composition, or preservation mode, or problem, there is no one acid or solvent
to use (NOT the same thing--be very careful here, as this terminology is exact
and precise, as you'd expect from chemists).
The SECOND thing you do is to determine what the disadvantages are and what
information you will use with the use of any chemical cleaning or treatment
method, and balance the costs and benefits. Scenarios vary. In some cases, the
morphology is more apparently important than the composition. In other cases,
there is most value in keeping a chemically pristine sample for delicate bio-
and geochemical work, and that's becoming more important every year. In still
other cases, the matrix has more to say scientifically than does the fossil.
The THIRD thing you do, if you establish that a solvent or acid is called for
in preparation, is to get yourself over to OSHA or comparable training on the
use of protective gear and equipment, and on which protective gear and
equipment this method calls for. You have a right to know this (indded, a
positive obligation), and such training is supposed to be provided free and on
demand by employers in the US.
I am appalled anew every time a case comes to light in which someone heard
about a chemical prep method and never read up further before deciding to use
the same. That's voodoo science and has cost the health (and a few lives) of
people (and destroyed quite a few specimens). I am further appalled anew every
time I hear about careless lab prep methods being passed on through oral
history and ancestor worship instead of formal qualified lab training. When you
have a chance to do it right from the ground up, take it.
Cheers, Sally Shelton
National Museum of Natural History