(a) Notwithstanding any other provision of this Title, the following nonconforming uses may be declared to be public nuisances and, if so declared, shall be terminated in accordance with the provisions of this Planning and Zoning Code. Nothing in this section shall affect the legality of previous orders requiring the termination of nonconforming uses, nor extend the time limit established prior to enactment of this section for the termination of nonconforming uses.
(b) In all zoning districts, the following nonconforming uses shall terminate and be discontinued as set forth herein:
(1) A nonconforming use of land, no part of which involves the use of a building or structure, or a nonconforming use of land, any part of which involves the use of an accessory building or structure with an assessed valuation of ten thousand dollars ($10,000) or less, shall terminate and be discontinued not more than three years from the effective date of this section or three years after such use becomes nonconforming.
(2) A nonconforming junk or wrecking yard shall terminate and be discontinued not more than three years from the effective date of this section or three years after such use becomes nonconforming.
(3) A nonconforming sign shall terminate and be discontinued not more than six years from the effective date of this section or six years after such use becomes nonconforming. However, in a Residential District, a sign maintained in connection with a nonconforming use may be continued for the duration of the life of such nonconforming use, provided such sign does not exceed three times the permitted size of signs in a Residential District and is otherwise conforming.