I have been downloading some fine files from the Internet for playing on my Disklavier.
In some cases while the only instrument that seems to be listed is "GRANDPno" there seems to be a "twangy" sound somewhat like a honky tonk piano or a piano with tacks in the felt that usually accompanies but sometimes contrasts with the acoustical piano music.
There does not seem to be an instrument to remove on a track or channel.