No junk dealers, part of whose business is that of disposing of old, obsolete or wrecked automobiles and dismantling same, shall perform any of such work in the streets or upon sidewalks adjoining their yards or permit or cause to be placed upon sidewalks or streets adjacent to the property used by them as junk yards any oil, grease or other like material from the automobiles, or parts thereof, making dangerous use of same by the citizens, and no automobiles shall be piled one upon the other in the yard, nor shall the chassis or other parts of the dismantled cars be piled in a manner adjacent to the street line liable to cause injury or damage in the use of the street or sidewalk, as a result of junk so piled slipping or falling into the fence and onto the sidewalk or street. (1973 Code §118.21)