Literally Google image search for Batman and Arkham City newspapers/wanted posters, etc., scale them in a DTP program, and print them really small. Use PVA and glue to moisten them on the backs and then glue to the bases, wrinkling them carefully with tweezers and an old brush. Once happy, let it dry and give it a very light wash of sepia ink. You might find its best to lightly spray varnish the paper first so the ink doesn't run, but often I quite like the rain-soaked look :-)