Colo. Rev. Stat. § 30-26-106
It is the duty of the county treasurer, when there are sufficient funds in his hands to the credit of the redemption fund to pay in full the principal and interest of any such bonds, immediately to call in and pay as many of such bonds and accrued interest thereon as the funds on hand will liquidate. Such bonds shall be paid in the order of their number; and, when any bonds or coupons issued under this part 1 are taken up, it is the duty of such treasurer to certify his action to the board of county commissioners, who shall cancel the same, so that they can be plainly identified, and cause a record to be made of the same. When it is desired to redeem any of such bonds, the county treasurer shall cause to be published for thirty days, in some newspaper at or nearest the county seat of the county and in a newspaper published in the city of Denver, a notice that certain county bonds, by numbers and amounts, will be paid upon presentation, and at the expiration of thirty days such bonds shall cease to bear interest.
C.R.S. § 30-26-106
For clarification of terms and requirements for notice by publication, see part 1 of article 70 of title 24 .