Workers used chisels and hi-tech laser technology to scrub grime from the more than 24,000 blocks of stone that make up the 183ft (55.8m) tall tower.
A safety clip or retainer must be installed to prevent attachments, such as chisels on a chipping hammer, from being unintentionally shot from the barrel.
The rough carving is made following that outline before the final carving is executed, for which the carver may use up to 100 different chisels.