The sale or conveyance of any interest in real property of the City may be negotiated and a purchase agreement entered into by any practicable means, including a public auction or private sale, subject to approval by the Council in the form of adoption of an ordinance. The proceeds of any sale of such property shall be used as far as possible to retire any outstanding indebtedness incurred by the City in the purchase, construction, or improvement of this or other property used for the same public purpose. If there is no such outstanding indebtedness, the Council may by ordinance or resolution designate some other public use for the proceeds.