I tend to run across hand tools from barn and workshop cleanouts. There's usually some level of dirt and rust. There are different things for cleaning metal. Sometimes it's a wire wheel and steel wool. Sometimes it's a bath in dilute muriatic acid. I've been tinkering with electrolysis using washing soda. I think i like that the best. I keep the best tools for my own use and wholesale out the rest to a fulla that has his own used tools selling place. It's really popular with the tourists & summer people.