Natural Science Forum / Biology / Paleontology / June 2004

You can try various plastics.  Polystyrene (which you can get by
dissolving white foam coffee cups in toluene) makes a fairly
acceptable coating for fragile, unminerailized fossils like leaves.
This was actually suggested in a paper a couple of decades ago and
seemed to work when I tried it on some fossils that didn't really need
it.  I imagine that Polyurethane might work.  These seem to be a one
way street.  Once the object is encapsulated, getting it out in one
piece is said to be unlikely.

Someplace around here I have a paperweight from the Austin airport
souvenir stand with a scorpion ecapsulated in some clear plastic.
Looks fine, so what you want to do probably is not impractical.