The Commissioner of Highways shall, as promptly as practicable, make an inventory and appraisal of all road machinery, equipment, teams, material, and supplies on hand or belonging to the local highway authorities of any county that returns to the secondary state highway system or any district thereof that may be deemed by him suitable for work on the secondary state highway system and shall file such inventory and appraisal with the Board. The local highway authorities may, if they so elect, turn over to the Commonwealth such road machinery, equipment, teams, material, and supplies at the appraised value thereof, which shall be paid within two years out of funds available for expenditure on highways in the secondary state highway system, or, if they so prefer, the local highway authorities may retain or sell any of such property otherwise or, if they so elect, may turn over to the Commissioner of Highways all or any of such property for use upon the secondary state highway system without reimbursement therefor. Any sums received by the local highway authorities under the provisions of this section shall, so far as may be necessary, be applied on account of obligations previously contracted for county or district highway purposes and the balance, if any, for general county purposes.