Today at the old park, I was going slow and paying attention to iffy signals. At this park, anything over 6" is old....so I get a 12-37 at 8" deep. In Andy's book when talking about the Old US Coin Program, I remember reading something along the lines of "if you skip out on 12-37 because you're almost certain it's a zinc penny, you're crazy." So at 8" I figured what the heck? After hitting 8" out pops 2 wheat pennies and a merc all stuck together. I couldn't believe it. Still I would've thought the signal would've been higher, but it wasn't. I'll post pics in a later thread, but in my opinion this throws a wrench into what I decide to dig in the future. Thanks for that bit of advice Andy!!