What was found
MCO - FLT 1020 EN ROUTE PHL TO MCO. F/A IN AFT OF CABIN REPORTED BAD ODOR AND BURNING IN THROAT. REPORTED THAT IT DISSIPATED IN DESCENT AFTER 10,000 SIGNAL. FIRST ADVISED OF PROBLEM 50 MIN INTO CRUISE AT 40,000FT. TROUBLESHOT TO MID LAV BEING ON MEL AND NOT BEING SERVICED FOR SEVERAL DAYS AS A RESULT. REMOVED A TWO FOOT OBSTRUCTION FROM WASTE DUCT IN FORWARD CARGO COMPARTMENT. ALSO, SERVICED THE LAVATORIES. FINALLY, REMOVED AND REPLACED THE HEPA FILTERS.