The proceeds of the sale of any refunding bonds shall be applied as follows, either: (1) To the immediate payment and retirement of the obligations being refunded; or (2) if not required for the immediate payment of the obligations being refunded, such proceeds shall be deposited in trust to provide for the payment and retirement of the obligations being refunded, but provisions may be made for the pledging and disposition of any amount in excess of the amounts required for such purposes, including, without limitation, provision for the pledging of any such excess amounts to the payment of the principal of and interest on any portion of such refunding bonds or series of such refunding bonds issued for the purpose of providing amounts in addition to the principal amount and premium payable with respect to the outstanding obligations to be refunded.
7 Del. C. § 6418