A Carrier Mechanic described his involvement with an A320 cabin door-1R; slide removal and replacement due to inadvertent slide deployment by Contract Ground Cleaners. Approximately six months later; at a 'C' Check; the door slide bottle was found with safety pin still installed.

Narrative

I was called and asked to come into work; due to the Door R1 slide was deployed by a Contract Ground Crew Cleaner. I arrived at work around XB00 and proceeded to set up the delivery of the replacement slide. Myself and a Mechanic proceeded to remove the slide and put it in a safe place for shipment. I then briefed the Contract Technicians to coordinate the installation of the slide the next morning. I then departed at about XC30.I arrived the next morning at XA00 and the slide arrived around XC00. I tasked the Contract Technicians with their jobs. I reprinted the paperwork and could not pull up the graphics. The Mechanic was assigned the RII duties. The Contract Technicians installed the slide while I assisted on lining it up with the girt bar. During this time; I was being pulled away to answer the phone and coordinate with Maintenance Control and Operations about the aircraft and flight. I actually did not see the Mechanic do the RII on the slide; due to I was taking care of my responsibilities.I then started to service the door assist bottle after I replaced the disc and the shear pin. The old shear pin was difficult to remove. But it was finally removed and I serviced the door assist bottle per the AMM. The plane was released for service and departed. The pin was found in the slide at an 'A' Check inspection.The lack of graphics did not help due to the computerized document viewer had a fault and would not allow graphics to be seen on the program and the regular computer. Reported to the Supervisor and a report was filed.I suggested a review of the RII items per carrier manual and a review of the RII items every three months; if the person has not done an RII signoff in the previous three months and a review of human factors.