Some forty or so years ago, a lady asked my dad if she could do some metal detecting on a portion of the farm. She turned up a spanish dagger from the conquistador days, probably the Cortes expedition. I've found various doodads,various intact bottles with an iridescent sheen from the sun, Mexican coins, rifle shells from the buffalo hunter days (I think), arrowheads galore, and 1920's auto parts. All of it interesting to me, none of it valuable, I don't guess.