Whenever it is necessary for the safety of the public, the City may remove any obstructions, hazards, or nuisances from the rights-of-way; and anyone causing the obstructions, hazards, or nuisances shall be responsible for reimbursing the City for the expense of such removal. The owner or operator of any vehicle which has spilled, dropped, dumped, or in any manner deposited any matter upon the right-of-way shall cause the right-of-way to be cleaned to the satisfaction of the City Engineer. Upon failure to do so, the City may cause to have cleaned the rights-of-way, and the costs thereof shall be charged to the person or persons so responsible.