Ted Hu et al;-
    Not only that BUT I have seen some pleistocene Olives that have
lost some color but still have a pretty good shine. Light rubbing oil
is best. It is guaranteed to keep the shell in pristine condition for
the balance of your life and that of your inheriting children. Of
course, some do better than others----but it will require someone
else to list shells according to their post-life lives.
   Art