Colo. Rev. Stat. § 24-18-204
State officers, county officers, city and county officers, city officers, and town officers, as well as all other local government officials, and their deputies and clerks, are prohibited from purchasing or selling or in any manner receiving to their own use or benefit or to the use or benefit of any person or persons whatever any state, county, city and county, city, or town warrants, scrip, orders, demands, claims, or other evidences of indebtedness against the state or any county, city and county, city, or town thereof except evidences of indebtedness issued to or held by them for services rendered as such officer, deputy, or clerk, and evidences of the funded indebtedness of such state, county, city and county, city, or town.
C.R.S. § 24-18-204