As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER T/O FROM ATL WE HAD A "DIRTY SOCK" SMELL IN THE AIRPLANE. IT SEEMED TO DISSIPATE DURING CRUISE, BUT RETURNED AS WE DESCENDED INTO CVG. PERFORMED DUCT BURNOUT BOTH LEFT AND RIGHT ALSO APU. NO ODORS. INSPECTED LT & RT ACM'S. NO TROUBLE FOUND. RPLD BOTH RECIRC FILTERS. FOUND DIRTY. RAN ENGINES AT T/O PWR- NO ODORS.