[motto (RIP)]

That's what the French refer to as the 'Iron Harvest'. Each farmer has a particular location where they deposit their finds for collection.
We were being shown around Bullecourt by a local resident and stopped to look at a little shrine in the corner of a field. Right alongside was a small cache of ordnance waiting for pickup, a couple of artillery projectiles and two mills bombs.
Claude, the local, had a practised eye for such things on the ground and walking between the crop rows easily found a couple of shrapnel balls for those who wanted them.
Another concern apart from explosive ordnance of course is gas shells or canisters.

David