So, I'm dismantling the Kranich & Bach Mission style upright piano
I recently purchased.  As I am removing the keys from the keyframe
I'm thinking to myself, "Wouldn't it be nice to find some gold coins
hidden beneath?"

Halfway through what pops out but a shiny gold coin, and then another!
"Eureka!" says I.  Take a look at my good fortune:

https://en.numista.com/catalogue/pieces147615.html 

Dave Krall