What was found
FLT#939, JFK-SJD. 'HEAVY DIRTY SOCK SMELL DURING DESCENT THROUGH 5000 FT AT 1000 FT DESCENDING SMELL WAS EVEN STRONGER ,WE OPEN COCKPIT WINDOW DURING TAXI IN. ( PACKS );COMPLIED WITH INFO NOTICE 2017-T015K AND TSM 05-50-00810-831-A. PERFORMED DECONTAMINATION OF ECS SYSTEM PER AMM 21-00-00-615-802. NO SIGN OF ODOR NOTED DURING DECONTAMINATION . PERFORMED IDLE ENGINE GROUND RUN PACK DECONTAMINATION PER AMM 71-00-00-810-801. COULD NOT DUPLICATE ODOR IN CABIN OR COCKPIT. REPLACED L/H AND R/H RECIRCULATION FILTER PER AMM 21-21-41. AFTER ENGINE RUN NO HIGH OIL LEVEL CONSUMPTION NOTED. PERFORMED INSPECTION OF APU PER TSM 49-00-00-200-811-A WITH BLACK LIGHT. NO SIGN OF OIL LEAKAGE NOTED. UNABLE TO DUPLICATE DODR EVENT THROUGH APU OR ENGINES. PER MCC FURTHER TROUBLESHOOTING REQUIRED DUE TO HISTORY OF AIRCRAFT ODOR EVENTS.'