@praxeology interesting thoughts. I've seen some people make BLO without additives by heating it up to just below the flash point. Not sure if they did that in the past?

Also, I imagine oil soaked rags would need a lot of processing before being made into paper...I think the oil would mess up with the hydrogen bonding needed for paper making, but maybe they just used a lot of harsh chemicals to clean the fibers before processing for papermaking? Those factories were quite toxic....