Comment by jacquesm

That's part of the story. The petroleum based part will go in a few years, what remains is the protective layer of wax that matters. I've bought some military surplus stuff that was coated in it, at first I didn't know what it was and then once I found out about it (and how to remove it) I was super impressed by how effective it is in preserving all kinds of materials from time's teeth. In particular these were parts for a 1940s vehicle, NOS that came out of the covering as though made the other day.