People have varying degrees of sensitivity to this, but I'm sure
you'll not be able to get it out completely, no matter what you do,
so I suggest finding a non-mouse infested piano to start with.

Go search on Craigslist.  Pianos are cheap, a whole lot cheaper, in
time and cash, than trying to get rid of this odor.  It's a pheromone
in the urine that can attract other mice from a mile away, and the
use of chlorine bleach in a piano will cause horrible rusting of the
strings and pins later on.

Gordon Stelter