It shall be unlawful to allow or permit vehicles to be brought back on the streets, alleys, or other public places of the city, or to continue, if unloaded, on such places, after they have been unloaded, until the hounds, couplings, or running gears of such vehicles have been thoroughly cleaned off, so that such gravel, sand, dirt, or other loose materials will not be strewn underneath the vehicles, along the streets, alleys, or other public places.
