Whenever such petty cash fund becomes low or depleted, the city clerk shall prepare vouchers covering such expenses as have been paid from the petty cash fund and shall process in the same manner as all other items of indebtedness against the city. Warrants issued therefor shall be payable to the petty cash fund and shall be deposited therein to restore such petty cash fund to its original amount for use as herein provided. (Prior code § 1-414)