20-60 is the gold range and where the most junk resides in (less iron). All detectors have issues there. I can't tell you how many times a gold necklace or ring showed up under foil, tabs and the like. Good targets can easily have the same signature as junk targets, It's why we move around targets, use AM, lift and lower the coil, and listen for anomalies in the sound to get a clearer picture in our minds. And why everyone says, "when in doubt, dig". When you see someone have a good day in a pic, some don't show you all the trash they dug as well, some do.