Lensman, are you talking about Washington square park in San Francisco , CA ? I'm 2 hrs. south of you then
I've done a lot of SF park hunting over the years, and pulled hundreds of silvers from those parks. But when it comes to "hunted out" slogan, don't make the mistake of thinking that , since you can find easy clad, that, therefore it's not "hunted out". Or that the prior hunters "missed those", etc.... Because the more hard-core turf hunters pass all shallow signals (clad). And hone in, instead, on deeper silver/wheaties whispers.
Thus yes, I have no doubt the parks there are riddled with clad, zinc, etc.... Some of the guys I hunt with up there may end a several-hour hunt with only 8 coins, for example. But 5 or 6 out of the 8 will be old (silver, wheaties, or whatever). Contrast to if a person wanted to spend that several hours digging all the loud bongs, then sure: He could end up with 50+ clad coins easy. But I much prefer old coins, over clad anyday. Ie.: I'd rather find 1 silver dime, than 10 new ones. Example: A buddy of mine dug 25 silver coins, and about 70-ish wheaties, from a single park there in a single day. When I asked "how much clad did you find?", he had probably less than 10 clad (deeper clad dimes that had fooled him).
You may be thinking that you can dig both shallow & deep, and therefore have the "best of both worlds", right ? Ah but it never works out that way. By stopping for all the clad, your ears become subconsciously tuned to the loud bongs, and you thus spend your day digging all the loud easy clad.