Hi 93vector, love them old buckles! And some very nice Buttons there as well! The silvery looking Button on the last picture is probably made of Arsenic Bronze, 17-18 Century. I find large amounts of them here in Europe. Some of them have outstanding designs. bye GA
Tombac and monel buttons, like the one you have with the engraved design, are becoming fairly valuable, highly collectible. By the by, best not to over polish them -- though they actually hold that desirable leaden color even when shined up. I've seen some collectors darken the design using harmless (easily removed) coloring agents, like ink. I recently sold three for $100.