What was found
AIRCRAFT WAS GROUNDED. AT IDLE POWER BELOW 10,000 FEET ACID OIL SMELL IN COCKPIT. ACCOMPLISHED SIC 05-96-70 NO FINDINGS. RAN BOTH ENGINES AT 80% N-1 IN MULTIPLE CONFIGURATIONS PACKS ON, OFF, BLEEDS ON. OFF, NO ODOR OBSERVED FROM ENGINES OR PACKS. ODOR WAS FOUND IN FIRST CLASS LAVATORY. LAVATORY WAS TORN APART SHROUD REMOVED, SUSPECT WRONG CLEANER USED IN LAVATORY SHROUD NEAR TOILET IS ETCHED WITH STAIN. LAVATORY SINK MUFFLER, PLUMBING, AND AREA CLEANED AND PUT BACK TOGETHER.