Nice finds you got there. Myself I'm more of a beach and waterhunter but I remember many dump sites around where I grew up in northern Germany full of stuff like that. Maybe I should go digging there again sometime. As kids we used to search for WW II junk to play with (which was forbidden of course, that made it even more fun). Close to every village there used to be at least one former gravel pit used as garbage dump before recycling systems were established during the eighties. These dumps were just covered up with sand but they still are there and nobody ever dug there. I still remember the exact locations of many such sites, they still must be full of bottles, porcelain, ceramics, relics from both world wars and who knows what else. People would call you crazy of course if you started digging up the old garbage dumps around here.