Etching with vinegar

[Mende]

I used it for mass rust removal ..I keep finding old hammer heads and files in old trunks in the attic ..and wherever i roam in my village ...( when im there. .)
I cut the top of a gallon bottle ..put everything in and duct tape it shut. . I call em Blacksmith Pickles . In 2 days . .all the rust and paint falls off and you can clearly see which parts are hardened as they show up black.