Hi, I'm new to this game and don't know if I'm starting out right, could use some tips. I have a mxt & start out in coin mode, set the gain to preset, dis to 3 I them pump the coil 3 times and set to ground. In two days I have found several pennies, one quarter, a 1931 tax coin and a 10k class ring. I have dug up a lot of junk like tabs, nails, but no dimes or nickles. I know there has to be a few of there around. I get a lot of hits on old carbon like ashes from a old Cole stove. I can't get the mxt to quit hitting on these small bits of carbon. Am I doing something wrong?