I believe a wax stamp was used back in the day..they would drip some wax on the back of an envelope/folded letter and pressed the stamp onto the wax before it went solid,hence embossing the design into the wax and sealing the letter shut.
Nice finds Val i know i was there when you found some of that clad and the CC coin fused to the key...but the Indian Head is in great condition. now only if this rain would stop..rain for the next 5 days