What was found
AT 1706Z, IN CRUISE FL350, .8 MACH, STRONG FUMES LIKE BURNING SULPHUR FROM FIREWORKS ENTERED THE COCKPIT. DONNED OXYGEN MASKS, DECLARED EMERGENCY, AND MADE LANDING. BOTH COCKPIT MASKS AND WALK AROUND BOTTLE WERE USED. INSPECTED BOTH ENGS NR 1 BEARING MANIFOLD AREA, FOUND NO OIL LEAKS ON EITHER ENG. OPENED BOTH NR 1 & 2 ENGS & PERFORMED VISUAL INSPECTION OF BOTH ENGS, FOUND NO LEAKS. PERFORMED ENG RUNS ON BOTH ENGS AND DURING RUNS INSPECTED AVIONICS COMP, UPPER & LOWER BAG BINS, BOTH PACKS RUNNING COLD & HOT, TEMPS NEVER GOT ANY ODD ODORS. PERFORMED PACK BURNOUT WITH APU IAW 21-51-00-03.NO SIGNS OF ODORS THE ENTIRE TIME. R & R COALESCER BAGS IAW 21-51-16-03. NEITHER BAG HAD ANY STRANGE ODORS.