BTW, it is highly unlikely that these crosses were actually made from shell fragments. To take a huge lump of 6-inch shell, hammer it into thin sheets, and then cut these into crosses ..... Far too labour-intensive, I would have thought. I am not aware of any part of a Creusot shell that would have already had these characteristics.
Some of the napkin rings purporting to be made from copper driving-bands are similarly dubious. In some instances the spacings of the cannelures and rifling-grooves do not match those of any known projectiles/ordnance of the period. An engineer by the name of Gerrans produced such items in his workshop in Mafeking. His keenness to obtain souvenirs ended in disaster when a shell exploded on his workbench, killing a passer-by and injuring himself and his foreman (the latter losing a foot). However, this did not put a stop to Gerrans's antics as, in 1902, he converted a Long Tom shell into a clock to be presented to Joe Chamberlain when he visited the town that year.