What was found
AFTER CLIMBING THRU 1000 FT AGL, CAPTAIN AND FIRST OFFICER BEGAN SMELLING FUMES AND WITHIN SECONDS A MASTER WARNING SMOKE AFT LAV MESSAGE. RAN EPC AND APPRC CHECKLISTS. MESSAGE WENT AWAY AND RETURNED BRIEFLY AFTER COMPLETION OF CHECKLISTS. MESSAGE WENT AWAY. AIRCRAFT HAS A DISTINCT SMOKE ODOR. NO OBVIOUS SMOKE OR BURNS. DETERMINED ODOR TO BE RESIDUAL SOAP FROM PREVIOUS COMPRESSOR WASH. PERFORMED DRYING OF INTERNAL ENGINE AIRFLOW COMPONENTS IAW AMM 72-00-00-100-801, STEP 4G, UNTIL UNABLE TO SMELL SOAP RESIDUE.