The clerk of said court shall write the name and address of each person named on such lists on a separate slip of paper. Each slip shall then be placed in a separate receptacle so designed as to conceal the information contained on the slip, and all the receptacles containing the slips shall then be placed in a box to be kept for that purpose, which shall be kept locked when not being used to draw a panel of jurors. The clerk of the court shall be the custodian of the slips, receptacles, box, lock and key.