What was found
WITH APU BLEED ON, FEEDING RT PACK, A STRONG, ACRID ODOR WAS NOTED IN CABIN. MAX COOL SWITCH WAS ON AT FIRST THEN SHUT AND ODOR STAYED THE SAME. RAN APU AND TURNED A MAX COOL SWITCH. DID SMELL A MILD ODOR. REMOVED CABIN ACM COALESCER SOCK. FOUND SOCK TO BE EXTREMELY DIRTY. REMOVED COCKPIT ACM COALESCER SOCK. CLEANED BOTH CABIN AND COCKPIT ACM COALESCER SOCKS. REINSTALLED SOCKS. OPS CHECKED GOOD IAW MM CH 21-51-00.