Buy a trashy piano and then touch its strings a lot. Get it out of your system.
But don't touch the strings on a piano you care about.
There are certain violin pieces that require abuse of the violin, and the violinists often get a trashy violin just for the purpose of playing such pieces. They would never do that on, say, a strad. Isn't there some John Cage piece that requires the violin to be set on fire? Definitely not to be performed on a strad. Anyway, that's where I got the idea--having a nice instrument and a beater instrument. You can do that with anything, really. Cars, spouses, whatever.