What was found
SMOKE TOILET CAUTION AT 3000FT FUMES AND HAZE IN AFT OF CABIN ON FLIGHT 3727 MSP -AZO. AIRCRAFT RETURNED TO MSP DUE TO BURNING SMELL IN CABIN. AIRCRAFT LANDED SAFELY AND TAXIED TO A GATE. FOLLOWED WORK SCOPE FOR SMOKE/FUMES IN CABIN. RAN AT TAKEOFF POWER FOR 30 MIN WITH NO MSG OR SMOKE FUMES NOTED PER WORK SCOPE FOR SMOKE/FUMES IN CABIN/FLIGHT DECK/SMOKE TOILET MSG 200 + 900 REV C. OK FOR SERVICE. REPLACED BOTH COALESCER BAGS. PART # ON AND OFF 21BC123. ALSO NOTED LEAKS ON RIGHT ACM DUCTING. REPLACED SLEEVES PART # ON AND OFF 504-250. PART #ON AND OFF 504-225.