Any revenues or proceeds derived from property purchased or acquired by the council with funds given or delivered to the council for a specific purpose shall be used exclusively for industrial development in the contributing county. Such funds shall not be commingled with other funds of the council, but shall be kept and expended solely for industrial development within the county specified, for the retirement of indebtedness on industrial property in such county. Once the indebtedness on any property acquired by the council with funds specified to be used in a certain county has been paid in full, the council shall execute a deed to such property to said county upon request to do so by resolution duly adopted by the board of supervisors of said county. In the absence of such request from the board of supervisors of such county the council shall continue to maintain the proceeds or revenues derived from such property in the separate fund to be used for industrial development exclusively within such county furnishing said funds.