What was found
AIRCRAFT WAS GROUNDED: FUMES REPORTED IN CABIN. ONCE ON CLIMB OUT BUT DISAPPEARED QUICKLY. NO FUMES DURING CRUISE. FUMES RETURNED ON DESCENT AND WERE STRONG. ACCOMPLISHED QRH AND TURNED #2 PACK SWITCH OFF AND FUMES DISSIPATED. NOTE: BOTH FUMES EVENT WERE AROUND THE SAME TIME THAT ENG ANTI ICE WAS USED. MAINTENANCE ACCOMPLISHED SOF WORK CARD 08L00021001. FAN BLADES WAS REPORTED CONTAMINATED ON BOTH ENGINES. FAN BLADES WAS CLEANED OF CONTAMINATES. PERFORMED AIR PURGE FROM AIR CONDITIONING DUCTS PER AMM 21-00-01-100-801.