Any sinking fund established by any municipal corporation to provide for the payment of the principal of or interest on any bonds issued by any such municipal corporation pursuant to the provisions of its charter or of this subheading, shall not be invested by the fiscal officer of said municipal corporation having custody of said sinking fund except in the manner prescribed by §§ 6 and 7 of Article 31 of this Code. Any such fiscal officer having custody of the proceeds of sale of any such bonds is hereby authorized and empowered to invest said proceeds, pending the expenditure thereof, in the manner and pursuant to the provisions of § 22 of Article 95 of this Code.