The ones which had been making plastic phones for the budget smartphone market switched to making phones with aluminium backs and plastic frames, and then even switched to full unibody aluminium construction. (xda-developers.com)
It isn't plastic, but it is still lighter than many plastic phones of similar size. (phoneradar.com)
There was a time when the green cell phone revolution seemed right around the corner — corn - based plastic phones that you could plant when you got a new model. (treehugger.com)