In the mid 1990s, they tore out Rodeo grandstand bleachers (circa 1920s) in my town. Underneath them was hard-pan dirt, where ..... for 70+ yrs, trash had rained through the slats onto the hardpan below. Naturally, they would clean out the standing-debri after each event (cups, papers, cans, etc..) but of course, coins, tabs, foil, etc... get missed. When they started removing all the trusses, foundations, and such, it stirred up millions of targets in the dirt below. A literal OCEAN of aluminum, tabs, etc... All of this would only last a week or so, before fill-dirt was to be added for the newer incoming grandstands. There was simply no way someone was going to be a "hero" and look for nickels or gold rings. So we cranked our discrimination and went strictly for silver and copper. We were rewarded with 100's of silver coins, and even a $5 gold piece! That surprised me, as I figured all gold was disc'd out. It turned out that we had rejected only round tabs and below, but a $5 gold reads high enough to go above that
Did we miss a gold ring? Sure. But in my mind, if I wanted to angle for that, I could merely go to the beach and probably have a better ratio/chance of that. This was the time to go for the silver. There was simply no way to have it "both ways". If someone had gone in there with a relic-mindset mentality, he'd have never have progressed outside of a 10 ft. square area. So we cherry picked, in the limited time-window we had.