What do you think? I think there is a tiny piece of copper on some pieces. the little flap in the second last pic. This is just from 1 keyboard. Took a little work but my 14 year old did most while I broke down some towers.
I've seen that type of contacts in keyboards from the 90:es, scrapped a number of them too.
As I remember (and seen in the second from last picture), there is two gold plated pieces in each key, a small band across the flat flexible surface and the contact point pressed into the center of the rigid plate. To cut down on chemicals and space I cut off the band with scissors and popped out the contact point by bending the plate. The rest is brass and copper.
I don't have any yields on these components, I just tossed it in among all my pins and other gold plated scrap.