All such refunding bonds may be exchanged, dollar for dollar, for the bonds to be refunded, or they may be sold at not less than their par value, as directed by the board of county commissioners, and the proceeds thereof shall be applied only to the purpose for which such refunding bonds were issued. Such refunding bonds shall not be issued until the outstanding bonds to be refunded have been called in and canceled in an amount equal to or in excess of the bonds so issued, and all accrued interest on any such bonds to be refunded shall be paid before such refunding bonds are issued.
Source: L. 17: p. 156, § 4. C.L. § 8868. CSA: C. 45, § 220. CRS 53: § 36-7-4. C.R.S. 1963: § 36-7-4.