(a) The dismantling or wrecking of automobiles or the salvaging of metal materials for the sale or storage of the salvaged parts or material shall be permitted only in the "M-2" District subject to approval of the Board of Zoning Appeals.
(b) Automobile wrecking and metal salvaging, sale and storage shall be effectively screened on all sides by means of walls, fences or plantings. Walls or fences shall be a minimum of eight feet in height with no advertising thereon. In lieu of such wall or fence, a strip of land not less than fifteen feet in width and planted and maintained with an evergreen hedge or dense planting of evergreen shrubs not less than six feet in height may be substituted. Storage of materials shall not exceed the height of the screening.
(c) All existing automobile wrecking and metal salvage yards shall comply with the provisions of subsection (b) hereof within two years after the date of enactment of this Zoning Ordinance, or shall be discontinued and removed.