My grandfather used to manage a solid waste disposal station in Palo Alto. He got to be friends with a number of homeless men who made their living doing just that. The one guy I remember best (Bert) lived out of his 56 Chevy station wagon. He would dumpster dive for electronics and disassemble them to get at what had recycling value.

Really you don't want to do that at the dump though, as by that time useful items have been commingled with actual trash. Another memorable story is that there was one worker who couldn't deal with glass bottles if they had any liquid in them and would just freak out and put them in with the trash.