I have some bones and a skull from Wyoming.....sun bleached....the
real way....the skull was so old it was chalking away......I coated
it with dilute white glue....and it is perfect. No more
deterioration....
But, I am concerned that no one is stressing caution with these
bones.....The occurrences of mad cow disease have been minimal here
in the US,,,,,but I wouldn't encourage handling of bones by your
students.....maybe the glue coat would seal them enough to make them
safe....