Truth is, I've never seen a deck and I think I've only ever seen one punch-card in the wild that wasn't behind glass in a museum. Just some random info I picked up along the way. I got in in the 8-bit days so maybe I'd put my key on one of these:



I've got an idea about making something out of glass sometime. It wouldn't be as hard-wearing as stainless steel but would have some advantages. 256 bits is only 8x8