We used to be able to ship tons of mixed recycling to China and they'd separate it and get the good stuff out. Now nobody wants it. Clean aluminum is still pretty valuable to recycle, but hardly anyone really separates it out like that. Cardboard is also easily recyclable, but only clean, non-laminated cardboard (and no pizza boxes). The stuff that ends up in residential recycling bins is almost useless cause people don't know what to put in them (you'll find tons of pizza boxes) and paying somebody to separate them doesn't make sense financially. So what I've heard is that most of the time, your blue bin recycling stuff ends up at the dump. Pretty depressing.