The board may abolish its working cash fund, upon the adoption of a resolution so providing, and directing the transfer of any balance in such fund to the educational purposes fund, effective upon the adoption of such resolution. Thereafter, all outstanding taxes of such board levied pursuant to Section 34-57 of this Article shall be collected and paid into the educational fund. Any obligation incurred by such board pursuant to Section 34-31 of this Article shall be discharged as therein provided. Nothing contained herein shall affect the validity of any existing obligations of the board.