It is unlawful to throw, cast or deposit, or permit to be cast, thrown or deposited on any street, alley, sidewalk or public or private premises, except in places where the superintendent of streets shall designate, any glass, metal, broken ware, rubbish, trash, dirt or garbage, or any substance or thing likely to make such places unclean, or obstruct or injure them; and it shall be unlawful to carry any matter upon any street or sidewalk exposed so as to be offensive. (Prior code § 13.16.150.)