Mich. Comp. Laws § 427.206

Sec. 6. Said treasurer shall keep said surplus and moneys for, and credit the same to the person named in said affidavit as said guest, boarder, or person leaving the articles sold, and shall pay the same to said person, his or her agent or attorney, executors or administrators, upon demand and evidence satisfactory to said treasurer furnished of their identity: Provided, That if said amount be not claimed within 2 years from the date of sale, it shall be placed in and become a part of the contingent fund of the county.