Any sign now or hereafter existing which no longer advertises a bona fide business conducted or a product sold, shall be taken down and removed by the owner, agent, or person having the beneficial use of the building or structure upon which such sign may be found within ten (10) days after written notification from the Building Official, and, upon failure to comply with such notice within the time specified in such order, the Building Official is hereby authorized to cause removal of such signs, and any expense incident thereto shall be paid by the owner of the building or structure to which such sign is attached.