I just found and bought some “Butcher’s Wax”. I always wondered
what a butcher would do with wax, but it turns out it’s a brand
name. I found it in a specialty hardware store.
Designed primarily for wood, but also recommended (by Society of
American Silversmiths), along with Renaissance Wax, for
protecting steel tools from rust. I haven’t tried it yet, but
some of my mandrels need it pretty badly!