I've found a number of zinc canning lids on my place, but only clad coins. Under the lawn I found a large iron plate, and figured I'd found the cache. Didn't dig it right away, I savored the thought of there being a jar of silver coins under that plate, so let the suspense grow a few days. Then the bummer happened, I dug up the plate, and it was covering a water shutoff valve. You know, it's really not nice to disappoint and old man like that. I've still only found clad, dog tags, and toy cars along with zinc canning lids and various bits and pieces of automobiles, nothing old or good. I've added a lot of .22 brass out back, so that's a bummer also, but every now and then I have to try my own yard again.