I have the same issue at times. One thing you can do is "size" the target, this may help eliminate it. Another thing I'll do at times is dig a few inches and use my probe. If I dig down 3" and do not get a reaction from my pinpointer, I leave it. But, with all that said, a good exercise is, pass your coil over the target, size it, listen to the tone, esspecially around the edges, then, dig it. It's good to put a target to the tone so to speak. Do this exercise, and before too long, you'll know in a few passes of the coil whether you should dig or not.