I've got an old full size mattress/box spring that I need to dispose of (mainly because I'm moving from Austin to DC and don't want to deal with moving it). The bed is clean, but is pretty lousy in terms of comfort. My condo has dumpsters and the city does not provide heavy-trash pickup. Any ideas how I can get rid of it? Should I just squeeze it in the dumpster? Does Salvation Army or one of those groups want old crappy mattresses?