When any sign becomes insecure, in danger of falling or otherwise unsafe, or if any sign is unlawfully installed, erected or maintained in violation of any of this Chapter or other applicable codes of the City, the owner thereof, or the person or firm maintaining the same, shall, upon written notice of the Building Commissioner, forthwith in the case of immediate danger and in any case, within not more than ten (10) days, make such sign conform to this Article or other applicable codes of the City, or shall remove it. If within ten (10) days the order is not complied with, the Building Commissioner may have such sign removed at the expense of the property owner, lessee, or other person responsible therefor.