im thinking a roller crusher like this,

or the tire method with a basket hopper on top. the video here is made from a treadmill, which isnt difficult to get for free on craigslist.
the only benefit to this design over the tires is that the opening/crushing surface would be wider than the tire design. that would save on jamming.
please tell us what you come up with olddude. im interested in what works best to maximize your can load.