What was found
FLIGHT 2131, BOS - LGA - ELECTRICAL SMELL AFTER TAKEOFF THEN CLEARED, F/A NOTICED ODOR AT TAXI INTO LGA. PRIOR FLIGHT 2123, BOS - LGA, RETURNED TO BOS WITH A SMELL IN THE CABIN AND STRONG ELECTRICAL ODOR IN THE COCKPIT. MAINTENANCE ACCOMPLISHED JOB CARD 43L00021001 TO TROUBLESHOOT CABIN AIR QUALITY. NO DEFECTS WERE NOTED. LGA MAINTENANCE FOUND THE NR 2 HEAT EXCHANGER FULL OF COFFEE RESIDUE. CLEANING WAS SUCCESSFUL, OPERATIONAL CHECKS OF BOTH BLEEDS AND BOTH PACKS AT HIGH POWER WERE SUCCESSFUL. THE RECIRC FILTERS WERE ALSO REMOVED AND REPLACED.