I use to do this to my grandmas piano but with hotwheels when I was younger. boy did i get my ass beat!
I've seen a sound designer do this was in the studio one night and I was getting some live instruments recorded and i wanted a Koto but there were none so he clamped the strings like this guy did in the video which made sense because stringed instruments can replicated 1 another.
To be able to hear that you really gotta hear music everywhere. He's like an acoustic sample junkie. And tell me I wasn't the only one thinking while watching this "Damn, I gotta sample this!" lol