I've heard of a few in other states who say their old parks have been hit so hard by others that they are devoid of even obvious trash signals. I find that hard to believe but I suppose it's possible, but I can tell you that none of my old parks are devoid of tons of deep trash signals as well as many iffy deep coin signals. For that reason I guess I should feel lucky. While I think somebody may put the effort in to dig all targets above iron at a park and make it their mission, if the park has any kind of size to it I think it would take a life time of constant work to do. I know several of my old large parks are so trashy that I don't think 5 hunters could clean one of them out if they made it their mission and life's work to do. That's why I always chuckle when I hear people say all the parks are hunted out. Not until you dig each and every signal out of there, because coins CAN read lower on the scale for various reasons (masking, depth, being worn, being on edge, minerals, etc), and of course no machine can see past the first metal object it hits. Even if the coin is off to the side a good bit of a shallower trash target, if the field is in any way hitting that shallower trash target first it's impossible to see a deeper coin. That's just the nature of physics in magnetic fields. While some of the energy can warp around and past the first metal object, it's so depleted in strength that it can't provide enough of a hit for the machine to even see. That's what makes small coils and also gridding from two directions so important, but also why no place is really ever hunted out until every signal (iron or not) has been dug.
I subscribe to the theory of others that possibly the site had clean fill brought in. It's obvious that it's fill when it's say clay, but when good topsoil is brought in nobody will know it's fill. Finding a few old coins shallow in it could just be because they were brought to the surface during the leveling of the new layer of soil, or were in fact brought in with the new dirt.
I'm not saying a park, especially a small one, could have been cleaned out completely by a group of hunters. I'm just saying that is the lessor possibility IMO, at least in all the public sites I ever hunted. Heck, I even crack up when I go to a local fresh water beach and find round tabs in the dry sand many feet from the shore where wave or storm action couldn't have exposed them. Who is hunting these places? If they are ring hunting a beach they need to scoop every signal. Then I hear at some beaches in other states they are so cleaned out that you only find fresh drops from the day before, and if you don't get there hours before sunrise 20 other guys will have already beat you to those few signals. I'm just glad it's not that competitive where I hunt, on beaches or land.
