Bruce, new cents, old cents, wheat cents, zinc cents and Canadian Cents, all read in the coin range, +/- a notch or two. Depending on how long, and what type of soil they are in, gives them a variance of oxidation, which has a direct effect on how the machine reads them. Even a Minelab can incorrectly ID a penny. You have to remember that the machine reads what is on the surface of the coin (oxidation?), not what is underneath. So the surface may NOT truly ID which type of coin it is. Now, the obvious double beep shallow coins in the penny range are most likelypennies, BUT...I have also got rings and silver dimes in that same range. A better scenario is this: Last summer, I covered about 90% of a junior highschool just around the block from home. I knew there were tons of pennies, as those kids throw them at each other. So, out I went with a screwdriver, popping those coins out as fast as I could. Sure, over 80% were pennies, but out of those 1800 coins, I also got 8 rings, earrings and other clad. The total was around (???)$40.00.
So, my advice to you Bruce is to get very profficient at popping those shallow pennies, and save them. Dig them all! You will also find other surprises there too. I buy a gold coin every year with just my pennies. I am planning on buying my 9th gold coin this year! Get the drift <img src="/metal/html/smile.gif" border=0 width=15 height=15 alt="
">