Okay, this is interesting. ALL metal detectors detect metal. That is their function. They pass an electro-magnetic field across a buried object and register the changes in the field caused by the conductivity of the object. Since the beginning of the detecting hobby there has been a drive to make detectors that are able to detect only good targets. The manufacturers called it discrimination. While there have been improvements, it has been mostly hype. There's a reason for this. Most modern detectors use known values as a baseline. So a zinc penny will affect the field created by the coil in a predictable way as will a nickle, dime, quarter, and so on. Now we come to the problem. A wad of aluminum foil can give an infinite number of reading values depending on the size of the foil, how deeply it is buried, and even how tightly it is wadded. It can look' like anything. So one piece can be totally ignored by the detector while another piece can register as a coin or gold ring. The same goes for pull tabs. Depending on the design of the tab and how it is laying in the ground, it can register a conductive value that is in the nickle-to-gold ring range. The detectorist has choices. We can dig only targets we are fairly sure of. We can dig iffy targets and come up with more good stuff while also increasing the amount of trash we haul home. Or we can use the old detectorist rule of if it beeps, dig it and know we didn't miss anything worth having while needing a scrap metal bin at home. But a detector that finds only gold and silver? Good luck with that. It's far outside the bounds of modern technology.
Storm
