The following operations shall not be considered as creating a sign, and shall not require a sign permit:
A. The changing of the advertising copy or message on an approved painted or printed sign, or on changeable letter panels or bulletin boards specifically designed for the use of replaceable copy;
B. Painting, repainting, cleaning, and other normal maintenance and repair of a sign or sign structure.
(Ord. 81-11 Art. XIII § 6(F), 1980).