Notwithstanding any of the foregoing provisions, when any unclaimed property is in the possession of the police department in danger of perishing, or of losing the greater part of its value, or when the reasonably necessary costs incurred in the care and protection of any such property amount of two-thirds of its value, the police department may sell such property by public auction in the manner and upon the notice of sale of personal property under execution, if it is a thing which is commonly the subject of sale, when the owner cannot, with reasonable diligence, be found, or, being found, the owner refuses upon demand to pay the reasonably necessary costs incurred in the care and protection thereof. (Ord. No. 1483 § 1 (part).)