That all persons, firms or corporations engaged in the business of purchasing or selling secondhand or castoff material of any kind, which is commonly known and is hereinafter designated and referred to as "junk" - such as old iron, copper, brass, lead, zinc, tin, steel and other metals, metallic cables, wires, ropes, cordage, bottles, bagging, rags, rubber, paper and other like materials, shall be and hereby are defined, and held to be junk dealers within the meaning of this act [57-7-1 to 57-7-7 NMSA 1978].
NMS § 57-7-1