What was found
AIRCRAFT UNUSABLE . FUMES IN COCKPIT FROM DISINFECTANT IS OVERWHELMING. ESPECIALLY ON F/OS SIDE. SUSPECT FLUID IN THE LAV IS THE PROBLEM. WHEN LAV DOOR IS OPEN FUMES ARE EXTREMELY STRONG. FLIGHT CREW DEBRIEF REVEILED THAT ODOR /FUMES WAS COMING FROM LAV. WHEN LAV DOOR OPENED FOUND ODOR TO BE VERY STRONG. INSPECTED E&E, CARGO COMPARTMENTS , INSPECTED LAV COMPARTMENTS , NO ODORS/FUMES FOUND OR SIGNS OF CONTAMINATION . OPERATED, PACKS WITH WINDOWS AND DOOR OPEN, WHILE HAVING LAV RESERVIOR SERVICED AND FLUSHED THREE TIMES . CONTAINED SAMPLE OF ORIGINAL LAV FLUID RETAINED AS PER CREW AND MOCC REQUEST. OPERATED BOTH ENGINES WITH PACKS ON AND AIRPLANE CLOSED UP FOR FIVE PLUS MINUTES REF JRH. INSPECTED ALL VENTS AND COMPARTMENTS AGAIN NO ODOR/FUMES NOTICED. LAV SERVICED BY INDY (AIR TO GROUND CONTRACT CLEANERS).