Mich. Comp. Laws § 446.213

Sec. 13. (1) A pawnbroker shall not deface, scratch, obliterate, melt, separate, or break into parts any article or thing received by him or her in pawn, or otherwise or in any manner do, cause, or suffer to be done by others, anything that destroys or tends to destroy the identity of the article or thing, or tends to render the identification of the thing or article more difficult. (2) A pawnbroker shall not accept by way of pledge, pawn, purchase, or exchange any article or thing that customarily bears a manufacturer's serial number or other identifying insignia unless the number or insignia is plainly visible on the article or thing.