What was found
WHEN TURNING L OR R ON GROUND STRONG SEWER SMELL FROM AFT LAV A REA ODOR IS COMING FROM CLOGGED AFT DOOR SILL DRAINS. BEGAN UNCLOGGING DRAINS REF AMM 38-31-00-100-801. CLOG PERSISTS. PERFORMED ROUTINE SOAK OF AFT GALLEY DOOR SILL DRAINS IN REFERENCE TO AMM 38-31-00. AFTER SEVERAL HOURS AND USING VACUUM TO SUCK AND BLOW AIR THROUGH DRAIN ON OUTSIDE OF AIRCRAFT, NORMAL FLOWRATE WAS RESTORED AND ALL SCENTS WERE ELIMINATED.