What was found
(E81R) DURING FUNCTIONAL TEST OF PAX OXYGEN SYS FOLLOWING SCHEDULED SOLENOID SHUTOFF VALVE O/H. NOTED FLOW INDICATORS IN ALL SIX CABIN PAX OXYGEN MASK ASSY'S, STICKING. FOUND OILY TYPE FILM & EVIDENCE OF MOISTURE CONTAMINATION IN AFFECTED MASK ASSY'S. CAUSING FLOW INDICATORS TO STICK. PURGED OXYGEN SYS & REPLACED PAX MASKS IAW MM. SUSPECT MOISTURE INTRODUCED INTO SYS EITHER WHEN LINES WERE DISCONNECTED FOR OXYGEN BOTTLE/REGULATOR ASSY. MX AND LEFT OPEN, OR ACFT SERVICED WITH MOISTURE CONTAMINATED OR INCORRECT TYPE OXYGEN. OILY RESIDUE IN FLOW INDICATORS MAY BE PLASTIC DECOMPOSITION, HIGH AMBIENT TEMP AREAS. RECOMMEND A NOTATION EMPHASIZING CAPPING OXYGEN SYS LINE FITTINGS BE ADDED TO MM PROCEDURES INVOLVING OPERATIONS OPENING THE SYS TO THE AMBIENT ATMOSPHERE. ALSO RECOMMEND A SCHEDULED 6-8 YEAR OXYGEN MASK REPLACEMENT TIME BE ADDED TO THE MM 5-10-00-601, TIME LIMIT REQUIREMENTS.