Any property which has been acquired or turned over to the Police Department and has been classified in accordance with procedures existing in the Police Department as unclaimed or for which the proper owner cannot be ascertained shall be kept for a minimum of 90 days. After a period of 90 days, such property, except as provided in § 10-203, shall be sold at public auction to the highest bidder and the proceeds after expenses shall be paid to the City General Fund.