As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE DOING ANNUAL INSPECTION REPLACING VERY STIFF TANK HOSE IN THE WING - THE LEFT TANK ON BEING PULLED EXPOSED MOUSE NEST. THE NEST WAS FORWARD OF SPAR AND INBOARD OF TANK ALMOST FILLING 2 SPACES BETWEEEN RIBS. THERE WAS CONNSIDERABLE CORROSION.