Maryland Code, Business Regulation § 12-102

(1) merchandise acquired from an established manufacturer or dealer who holds a license under this title, other than a pawnbroker, if the dealer who acquires the merchandise keeps an invoice or other customary proof of origin for the merchandise;

(2) a metal acquired for use in dentistry by a dentist licensed to practice dentistry under Title 4 of the Health Occupations Article;

(3) coins; or

(4) the purchase of junk or scrap metal that is subject to the record keeping and reporting requirements under § 17-1011 of this article.

(1) accepts, in accordance with a posted return policy, the return of an item that the jeweler originally sold;

(2) accepts, in accordance with a published trade-in policy, merchandise in trade that the jeweler originally sold;

(3) repossesses merchandise that the jeweler originally sold, if the original buyer has defaulted;

(4) retains merchandise that the jeweler originally accepted for repair as a bailee for hire, if the customer who deposited the merchandise:

(5) accumulates pieces of precious metals in the course of performing repairs, remountings, fabrications, or custom orders; or

(6) participates in a remount sale.

(d)(1) A county or municipal corporation may not enact a law to regulate dealers or coins.

(2) This title supersedes any existing law of a county or municipal corporation that regulates dealers or coins.