In the category of "inquiring minds"... or "you can't make this up" I had to look this up.
(I was momentarily confused since OTD started this thread, that it might be one of those WI stories... It was not. and I should have known better than to question OTD in my mind, like that. Sorry OTD. )
HEre's a snip from the page in the Sunfire Architectural True Subwoofer, in our library.
Says to do it once a year, or more, if you live next door to Gene. Nothing about the "active ingredient." But, I would suggest/conclude that back in the day, in the Northwest where Carver was located, and where it's very wet most of the year, pure mink oil was more available and common - so I'd try to find the real weasel oil. I had some from when from Red Wing shoes, I used on my steel toed boots in the machine shop where I worked as a teen. I'll have to see if I still have it in my shoe-care kit, and if it has additives.