Wyo. Stat. § 37-9-703
The contracts herein authorized, or a certified copy thereof, shall be filed by the secretary of state in a special file to be kept for that purpose. On payment in full of the purchase money, and the performance of the terms and conditions stipulated in any such contract, a declaration in writing to that effect may be made by the vendor, lessor, or bailor, or his or its assignee, which declaration may be made on the contract or certified copy thereof, duly attested, or it may be made by a separate instrument, to be acknowledged by the vendor, lessor, or bailor or his or its assignee, and filed as aforesaid. The secretary of state shall collect a fee of five dollars ($5.00), for filing each of said contracts, and a fee of two dollars ($2.00) for filing each of said declarations, and a fee of one dollar ($1.00) for noting such declaration on the margin of the contract or certified copy thereof.
W.S. 37-9-703