What was found
DESENDING THROUGH 8000 FT WE STARTED SMELLING A MUSTY PAINT SMELL THAT ONLY GOT WORSE. WE TURNED OFF PACK 1 AND CLOSED THE CROSSBLEED AND THE SMELL WENT AWAY. FLIGHT ATTENDANTS DID NOT SMELL ANYTHING. ISOLATED TO THE COCKPIT.-REF TSM 05-50-00-810-831 & CREW COMMENTS SOURCE OF ODOR IS APU AND OR ENG 1. COS IS TYPE 1 AND TYPE 2 . FOUND ENG #1 JUST ABOVE FULL MARK. DRAINED TO PROPER LEVEL. INSPECTED APU COMPARTMENT FOUND APU OIL BETWEEN 1 AND FULL MARK.DRAINED TO PROPER LEVEL AS PRECAUTIONARY. REF AMM 12-13-79AND 49-90-00. ENG DRAINED 1 QT. AND APU 8OZ