Hello Cindy
You Can use ArmorAll to preserve the luster of the shell,
and the periostracum if present, and not for animal presivation.
Leslie

I hate to bring this up, but remember reading that someone said to use
Armorall to clean shells, but to either use the cleaner and NOT the
preservative or vice versa.  Can you tell me which it was?  Thank you.  Cindy

The opinions, comments, and advice offered by me here are mine alone.
As such, they carry as much weight as a feather in a snow storm.