Each bond or other evidence of indebtedness shall contain on its face a statement specifying the purpose for which it is issued, and it shall be unlawful for any official of the City to use the proceeds of the bond for any other purpose. All bonds and other evidences of indebtedness issued by the City shall be signed by the Mayor and countersigned by the City Clerk under the seal of the City. Interest coupons may be executed with the facsimile signatures of the Mayor and City Clerk. A complete and detailed record of all bonds and other evidences of indebtedness issued by the City shall be kept by the City Clerk. Upon the payment of any bond or other evidence of indebtedness, the same shall be marked “Canceled”.