What was found
PASSING 5500FT MSL AND LEVELING AT 6000 FT, HAND FLYING USING AUTO THROTTLES, ATTEMPTED TO TRIM AIRCRAFT MANUALLY WITH TRIM BUTTON ON YOKE. DURING TRIM A VIBRATION WAS FELT ON THE A/C. NEEDED MORE TRIM TO LEVEL, AGAIN VIBRATION OCCURRED DURING TRIMMING, 250 KTS, 6000 FT MSL, CG 27.8 PERCENT, AUTOTHROTTLES ON & ENGINES NEAR IDLE. INSPECTED TRIMMABLE HORIZONTAL STABILIZER. ON STABILIZER APRON, FOUND ON BOTH SIDES BOTTOM HALF SEVERAL FINGER SKIRTS MISSING RIVETS (55-10/8938). FOUND MANY PIECES OF PAPER WEDGE IN AND AROUND PITCH TRIM CONTROL WHEEL CHAIN. REMOVED ALL DEBRIS. PERFORMED ADJ/TEST PER MM 22-27-00-5 OP'S