Additive manufacturing using household waste

I've been thinking a lot lately about how consumers could make use of their household waste in additive manufacturing. I've posted previously on 3D printing using waste paper, but I'm also interested in other materials. Those I've been thinking about include aluminium cans, tin cans (which are tin-plated steel) and thermoplastics. My first thought was that the challenge would be getting the necessary temperature, but Markus Kayser's SolarSinter project, suggests that this is not really a problem (at least in sunny places). The remaining challenge is granularizing the waste material to be used for the sintering. This is less of a problem with the thermoplastics - they would probably succumb to a househouse paper shredder (although that wouldn't be sufficiently granular).