The Collaborative International Dictionary of English v.0.48:

Ragpicker \Rag"pick`er\ (r[a^]g"p[i^]k`[~e]r), n.
   One who gets a living by picking up rags and refuse things in
   the streets.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ragpicker
    n 1: an unskilled person who picks up rags from trash cans and
         public dumps as a means of livelihood

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "ragpicker":
   Arab, beach bum, beachcomber, beggar, bo, bum, bummer, dogie,
   gamin, gamine, guttersnipe, hobo, homeless waif, idler, landloper,
   lazzarone, loafer, losel, mudlark, piker, ragamuffin, ragman,
   rounder, ski bum, stiff, stray, street Arab, street urchin,
   sundowner, surf bum, swagman, swagsman, tatterdemalion, tennis bum,
   tramp, turnpiker, urchin, vag, vagabond, vagrant, waif,
   waifs and strays, wastrel