What was found
FLT #780, MBJ-JFK. DIRTY SOCKS SMELL STARTING DOWN FROM 8000. WE SHUT OFF PACK ONE THE SMELL PRETTY MUCH WENT AWAY. TURN PACK ONE BACK ON DURING TAXI SMELL CAME BACK; PERFORMED STAGE 2 CLEANING OF THE ECS AND ISOLATE APU BLEED AIR. RAN ENG #1 AND #2 35 TO 40 % N1 PER AMM 21-00-00-615-802. RECIRC. FILTER CHANGE IS REQUIRED AS PRECAUTIONARY. THE ITEM REMAINS OPEN. REMOVED AND REPLACED RECIRCULATION FILTERS AND PERFORMED IDLE LEAK RUN IAW AMM 71-00-00 AND AMM 21-21-41. CABIN ODOR NO LONGER PRESENTS. A/C OK FOR CONTINUED SERVICE.' (SUPPLEMENTAL INFORMATION ADDED TO THE DESCRIPTION)