It is unlawful for any person to permit to accumulate on any premises, improved or vacant, or on any open lot or alley in the city any lumber, boxes, barrels, bottles, cans, containers, junk or other materials that may be permitted to remain thereon unless the same shall be placed on open racks that are elevated not less than eighteen inches (18") above the ground, and evenly piled or stacked. (Prior code § 18-22-19)