The director may vacate any land or part thereof, or rights in land taken or acquired for highway purposes under the provisions of this title, by executing and recording a deed thereof, and the vacation revests the title to the land or rights in the persons, their heirs, successors, or assigns, in whom it was vested at the time of the taking. As oil, gas, and fluid minerals are not a part of and essential for highway purposes, all such rights heretofore taken, if any, are hereby vacated and returned to the person or persons in whom the title was vested at the time of taking, their heirs, administrators, executors, or assigns. Such reconveyance is subject to any existing contracts or agreements covering the property, and all rights and benefits thereof accrue to the grantee. The governor, on recommendation of the director, may sell and convey on behalf of the state the interests of the state in property acquired by purchase under this title and deemed no longer necessary for the purposes thereof, and the proceeds of the sale so far as practicable must be credited to the funds from which the purchase was made originally. With the consent of the persons, their heirs, successors, or assigns in whom the title or rights to the land were vested at the time of the purchase or acquisition, the director may vacate land acquired by purchase under this title which is deemed no longer necessary for highway purposes and which the director has determined that the cost of the sale exceeds the estimated value of the property, by executing and recording a deed thereof, and the vacation revests the title to the land or rights in those persons, their heirs, successors, or assigns.