On 5/7/2021 6:16 PM, Ralph Mowery wrote:
In article ,
says...

Probably linseed oil, that was the good ol wood protectant. It spontaneously
combusts if left in piled rags. If the shed caught fire it would have been a
grand sight.




I live in a small town and about 55 years go there was a fire that wiped
out a city block. The buildings were old and many had wood floors and
about 3 stories tall. Those floors probably had many layers of some
kind of oil on them. The buildings were brick on the outside.


In New England at least once a year one of the old mills would go up
like that as the wood floors were oil soaked. Most every town has a mill
building of some size.

https://en.wikipedia.org/wiki/Wood_Worsted_Mill