Originally Posted by unboggling
Your posts got me wondering, regarding trading up computing capability by selling older Mac and buying a different new or used Mac, what is the best and quickest way for a non-techie user to clean the old Mac of all account information and stray bytes on internal storage, while still leaving the OS and basic Apple-included apps for the potential buyers to try out and use?
And also, similarly, what is the best and quickest way to clean an iPad for resale?
After transferring your stuff to your new computer, boot from the Mac OS install disk or USB stick (or recovery partition, but I find having a USB stick more convenient). Run Disk Utility, select the drive, go to the Erase tab, click Security Options, choose "write a single pass of zeros" (multiple passes are pointless). Then click Erase, and wait... Then re-install Mac OS X.
For an iPad, just go to Settings->General->Reset->Erase All Content and Settings.