Nonconforming open storage yards, outdoor displays or junkyards in LS, CS or RS Districts. Any nonconforming open storage yard, or any outdoor display or storage of merchandise in connection with an auction establishment or store specializing in secondhand merchandise, in LS, CS or RS Districts, which is nonconforming, either because not permitted in the district or because not located within a completely enclosed building, may be continued for one year after the effective date of this chapter, provided that after the expiration of that period such nonconforming use shall then be terminated. However, no such use will be required to terminate if within said period it shall be located within a completely enclosed building. Any nonconforming junkyard in LS, CS or RS Districts may be continued for three years after the effective date of this chapter, provided that after the expiration of that period such nonconforming use shall than be terminated. However, no such use will be required to terminate if within said period it shall be surrounded with a uniformly painted solid fence no less than one foot higher than the highest elevation of the material stored within such junkyard, provided such fence shall be maintained in good condition at all times and its maximum height be seven feet.