The county recorder shall repurchase any unused documentary tax stamp sold by him prior to July 1, 1968. Documentary tax stamps shall not be accepted for payment of the documentary transfer tax after Sept. 1, 1968. Unused documentary tax stamps shall not be accepted for repurchases after June 1, 1968. On and after June 1, 1969, the county recorder may destroy all such adhesive stamps in his possession. (Prior gen. code § 2-31.01)