Make Sure the Phone Is Fully Wiped
The last thing you want is to buy an iPhone that has some hidden software loaded on it. The best way to prevent this is to make sure that the phone is fully wiped before you start using it. Some of the sites we listed above will guarantee that the phones they sell are wiped, and even random sellers that you find on eBay or Craigslist, will often mention that the phone has been fully reset. Don’t take anyone’s word for it. The first thing you should do when buying any used iPhone is to go to Settings > General > Reset > and then choose Erase All Content and Settings.