Those cache coins are very common in CA. They turn up en-masse at any place where coins earlier than about the 1920s are at. Ie.: very common at old town urban demolition sites, older parks, sidewalk tearouts, older yards, stage stops, etc.... I've found hundreds of them over the years here.
They have absolutely no value, despite some being incredibly old. But are fun to find d/t their an "age-indicator" that you might be in for some barbers or seateds
They must've left China in litteral barrells-full, where they in turn must've been stored for generations. Because some of the dates on those things (which go in "dynasties" of 50 to 80 yrs. or whatever) can date to even as far back as the 1600s! Yet show up in places that didn't even start till the late 1800's here.
Humorously, 1 was found in an indian midden archaeological site in the pacific northwest years ago. The archaeologists dated it to the 1600's, and were "all over themselves" with excitement, that this somehow proves the Chinese predated the Europeans .... and that some Chinese must've arrived all the way across the pacific in the 1600s, blah blah. But what the archies don't know, is these things are simply everywhere, sometimes yes that old, and that the age of them has absolutely no bearing on anything. Unlike American coins where you might reasonably assume that they tend to circulate for a max of 40 or 50 yrs, (with the circulation wear being proof positive of the time/length of circulation), yet these cache coins must've been collected and simply stored for millenia, in China, before even being released into circulation.