Hi, Tom!

I can tell you one success story for WD-40.   A number of years ago, I obtained one of the pinkish Conus pertusus
(excuse the spelling - I can't find this one in  the book right now) from the Phiullipines.   I kept it in complete darkness, and it faded hopelessly in less than a year.   On the recommendation of a dealer, I got another one and used WD-40 on it.   It is still bright and many years old.

Cordially,
Linda