It would all depend on
the consistency of the soil at any given area. I can take you to towns in upper NY state where it is basically all sand. You can use a metal detector, as we have tried many times, and walk for miles of beautiful beach where the detectors indicated a "treasure" with each step that you take. You can sink a shovel, turn the sand and see color streaks from black to rust orange -- the whole area, for miles and miles, is full of minerals that react to detectors.
So far we have detected "caches of arms" BUT, just for you, I will keep looking.