I attended the 2017 Process Control and Safety Symposium and Exhibition last October and had a chance to speak with Larry Whittaker of Raki Computers Recycling. Performing another partitioning and formatting of a computer disk does not guarantee that all the data is wiped clean. Even a broken hard disk is not 100% fool proof. Also, computer components have lots of nasty stuff that adversely affect the environment, like heavy metals and plastic. A solid plan for the careful destruction of data and computer components is a wise course of action. Take a look at this video, I think it will be highly informative.