Mich. Comp. Laws § 445.131

Sec. 1. No person, firm, partnership, association or corporation, or agent or employee thereof, in any manner, or by any means, shall offer for sale goods where the offer includes the voluntary and unsolicited sending of goods by mail or otherwise not actually ordered or requested by the recipient, either orally or in writing. The receipt of any such unsolicited goods shall be deemed for all purposes an unconditional gift to the recipient. The recipient may refuse to accept delivery of the goods, is not bound to return them to the sender, and may use or dispose of them in any manner he sees fit without any obligation on his part to the sender.