I find all kinds of stuff. I live in coal country here in the mountains. While riding to school a few weeks ago on the bed, I saw something strange looking on a bank as I passed it... I looked closer, and it was an open mne shaft, all covered with weeds! Most of the shafts were destroyed here when strip mining became popular.... I'll have to get some pictures...
I've found money and a filet knife so far while out riding the country....