C.R.S. § 42-4-2106

The lien provided for in section 42-4-2105 is perfected by taking physical possession of the motor vehicle and by sending to the department, within ten working days after the time possession was taken, a notice containing the information required in the report to be made under section 42-4-2103 . The lien is not perfected until the lien attaches in accordance with the schedule described in section 42-4-2105 (1)(b). The report must contain a declaration by the operator that a possessory lien is claimed for all past, present, and future charges, up to the date of redemption, and that the lien is enforceable and may be foreclosed pursuant to the provisions of this part 21.