The superintendent may approve the sale of improvements on restricted Indian lands when such improvements are appraised at not more than $500 and when the owner has submitted a written request that the sale be made and a statement that the improvements can no longer be used by him. The proceeds of all such sales shall be deposited to the credit of the Indian as surplus funds. Improvements consisting of buildings, etc., located on property within the Osage villages of Pawhuska, Hominy, and Grayhorse may, upon approval of the superintendent, be disposed of to other Osage Indians. The superintendent may disburse the surplus funds of the purchaser to consummate the transaction. Sale of such improvements to non-Indian or non-Osage Indians must be approved by the Commissioner.