Colo. Rev. Stat. § 5-2-210
Subject to the provisions on rebate upon prepayment contained in section 5-2-211, the consumer may prepay in full, or in part if payment is no less than five dollars, the unpaid balance of a consumer credit transaction at any time without penalty. A payment in the amount of a scheduled installment, other than the last scheduled installment, not identified by the consumer as a partial prepayment shall not be deemed to be a partial prepayment regardless of when the payment is made if the amount equals the next scheduled installment. If such a payment is applied by the creditor to the scheduled installment, the payment shall be deemed to have been made on the due date for the scheduled installment to which it was applied.
C.R.S. § 5-2-210
This section is similar to former § 5-2-209, as it existed prior to 2000.