Well, I've posted several times about the "scratch" sound some nickels and rings give on the Tracker IV in the tone mode-my favorite. It's because the low tone sounds like one. Today I found a really thin ring-unfortunately no gold markings-and it was just a quick single "scratch" low tone. Here's some extra info: whenever you slow down the coil, the signal gets better on nickels, rings, etc. and sorta breaks up all over the place on pieces of foil-with the exception, of course, of large pieces. Listen for that ":scratch"!