No machine can get all the deep coins in a trashy area in just one visit. You're going to have to keep going back to a producing site and swing your coil at various angles of attack each time you go. I would not notch out or reject any low conductive targets. Open your discrimination pattern to near All-Metal. Listen to every signal in the ground. Let tone be your judge for digging a target, not ID's or screens. Maybe one day you'll detect an old area in a North to South direction, then the next time you'll detect the same area in an East to West direction. Another time when you go back, you'll swing in a criss-cross (diagonal path) from your previous hunts. When you do happen to hear just a faint whisper of an iffy sounding target, swing your coil around this target from different angles, and try to isolate it from the other pieces of nearby trash. One swing angle will usually produce a better signal on a deep target mixed in with trash. That's how you're going to maximize finding old coins in a trashy site. Maybe when you get a real shallow trash target, like a pull tab, try swinging from all directions around the trash target to try and pick up any fainter/deeper targets next to it. And if you see any pieces of trash just laying on top of the surface, pick them up and put them in your trash pouch, then detect over that spot. To increase your chances of finding the deeper items, dig all shallow clad signals, and if you want to go a step further, start digging all large and shallow trashy targets, then recheck the area.
Nobody, and no machine, can hunt out a trashy site in one trip there. If we could find every old coin in the ground at a trashy site in one single visit, what fun would that be? This is just not the case with any machine on the market today.
I love to revisit old sites that have been heavily detected throughout the years, in addition to my current sites that I've been pounding time and time again, and pull more old stuff from them. It gets more challenging and more rewarding with each and every oldie you dig with successive hunts. Hunting "style" is going to make you a more successful hunter.
HH,
CAPTN SE
Dan