Age of facility a factor. An example ,if a gate had a ticket booth in the sixties and now booth and gate are gone. I,d be looking for pinch points in traffic patterns and lounging areas where people congregated. Concession stands, Shade ,seating ect. Sports fields too where activity generates a lost item. There,s usually a lot of bottle caps ,foil and pull tabs but there,s stuff in those areas for the patient diggers.