Any sign(s) and fixture(s) now or hereafter existing which, for a period of sixty days, 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, lot, or structure upon which the sign may be found. Fixtures that are no longer used shall be removed. Signs that are not used because of a vacant building shall remove the fixture or replace the sign face with a blank. Upon failure to comply with this provision, the building official is authorized to cause removal of the sign and any expense incident thereto shall be paid by the owner of the promises or filed as a lien against the property.