What was found
FT # 2133, DESCENDING THRU 12K, GOT STRONG JET EXHAUST SMELLING FUMES IN COCKPIT. GOT VERY STRONG SMELLING BOTH PILOTS WENT ON O2. TURNING RECIRCS OFF BRIEFLY HELPED, BUT STRONG FUMES CONTINUED. NO SMELL DETECTED IN CABIN; PER FIM 21-20-00-810-801A & 803A PERFORMED INSPECTION OF THE AREAS THROUGHOUT CABIN / FLT DECK / AVIONICS AREAS W/ NO DEFECTS NOTED. OPERATED APU BLEED, ENGINE BLEEDS WITH EACH PACK 1 & 2 SEPARATELY. NO DEFECTS NOTED. ALSO FIM 25-30-00-810-801A ABNORMAL GALLEY SMELL PLUS 25-40-00-810-801 LAVATORY CHECKS NORMAL. ACFT OK FOR CONT SVC AT THIS TIME.