Green’s Dictionary of Slang

1. (US) a collector of rubbish, a ‘rag-and-bone’ man.

1930		D. Ahearn How to Commit a Murder 87: The tire you would throw away from your autombile, that is sold to a junky, who sells it to a place where they make a new tire out of that old tire.
1953		S. Bellow Augie March (1996) 11: Mr. Anticol, the old junky [...] and his alley calls for rags, old iron.
1975		J. Ryan Remembering How We Stood 32: Wilfred Bramble (later to become famous as the elderly ‘junky’ in the television series ‘Steptoe and Son’).

2. see junkie n.