Note how the top key has warped. This is one of the reasons why a key will stick. Mice Mice love reed organs. The many nooks and crannies offer excellent possibilities for nesting. A mouse chewed on this safety valve from the back of a reservoir to try to get inside.
Mice also enjoy eating the soft calfskin used for gaskets and seals in various parts of an organ.
They will also eat through various wooden parts to find something they like, pitman rods, swell shades, and mutes. Dampness can cause brass parts to develop verdegris, especially when it is in contact with felt or leather, both of which attract and absorb moisture. The steel connecting rod shown here has rusted from exposure to dampness. Note the rust under the felt-covered tip. Moths Moth larvae are actually the culprits.