Mary Fisher wrote:


Since we're lapsing into nostalgia, my late father used to drive a steam
roller (i.e. real steam - none of your diesel rubbish!) back in the
1920's.
He told me how the workmen would keep the most recent new coal shovel for
cooking and - using a little lard oil

What's 'lard oil'?

Oil made from lard.
IIRC, you take lard, and press it (cold) into some muslim or other
fine cloth.
The oil that comes out is lard oil.
A very good lubricant.