Petty cash funds hereby authorized may be used to provide for payment of any authorized expenditure of not more than twenty-five dollars ($25). No petty cash fund may be used to pay regular employees or current accounts which are payable monthly. No money shall be advanced from any petty cash fund except in accordance with written instructions issued by the board of county commissioners: Provided, That a resolution may authorize the county clerk to establish a petty cash fund in an amount of not to exceed five hundred dollars ($500) to be used to redeem unsold fish and game licenses returned by authorized dealers. The county clerk may replenish the fund as it becomes necessary from receipts from the sales of fish and game licenses.