Cleaning cast iron pans with sorrel leaves?

I do not claim to be a cast iron historian, nor have I spent much time researching historic cleaning methods... but I came across an article on facebook that says pioneers in the USA in the 1700's and 1800's use sorrel leaves to clean their cast iron pans... specifically to get rid of rust. It is supposed to release oxalic acid which is supposed to dissolved rust.

Has anyone else heard of this? Sounds like a pretty cool thing if it is true.

Huh, I wonder how they would manage to do that? I would imagine that you would be shredding the plant material trying to scrub a pan with it. Maybe it was used as a sort of soak?