Here's my .02c : The trick to finding gold is not to lower your disc. , and be a hero in junky parks. Instead the trick is : Location Location Location.
Hunt swim beaches , for better odds and more conducive conditions for jewelry losses . Not to mention that digging in sand is easier. And if you MUST hunt turf in your quest for gold jewelry, then even then: Not all turf is the same. For example: Sports turf location (soccer, around the goal posts, for instance) is going to be less punishing that anything that involves picnicking. Because the moment you add picnicking, is the moment you introduce foil (for the food wraps) and tabs and can slaw, for the soda cans. And the moment you add BBQ pits, is the moment you add molten aluminum nuggets.
Other land locations are : sand volley ball courts, PT courses, hand-wrestle pits, mud wrestle pits (once they're dried out), etc....