Any outdoor sign now or hereafter existing which no longer advertises a bona fide business conducted or product sold, shall be taken down and removed by the owner, agent or person having the beneficial use of the building or structure upon decision by certified mail from the Zoning Inspector. Upon failure to comply with such notice or failure to appeal such decision within the specified times, the Inspector is authorized to cause removal of such sign. any expenses incurred by such removal shall be paid by the owner of the building or structure to which the outdoor sign is attached.