Notwithstanding any other provision of this Zoning Ordinance, any sign or commercial billboard in existence at the effective date of this ordinance in any residential district that was zoned other than residential by the previous Zoning Ordinance shall, at the expiration of five years from the effective date of this ordinance, be discontinued. The Municipal Planning Commission may, however, permit the continuance of such sign or billboard by special permit.
(1970 Code Sec. 32-71)