April 10, 2014, 10:46 AM — Before you sell or recycle your old smartphone or tablet, you need to wipe it clean, for security's sake. It's not always as easy to do as you might think -- but I'll tell you how, for iOS, Android, Windows Phone, Windows 8, and Blackberry.
Your smartphone or tablet has your entire life on it, including your contacts, records of your incoming and outgoing phone calls, your text messages, and much more. It's pretty much impossible to try and delete every trace manually. You simply won't be able to do it. Instead, you need to give it a much deeper cleaning, essentially putting it back to the state it was in when fresh from the factory. How you do this varies from mobile OS to mobile OS. Here's how to do it for each.
For versions 5, 6, and 7, launch the Settings app, then tap General --> Reset. You'll come to several options on the screen that appears, including those for resetting your network settings, resetting, your home screen, and others. But the one you want is "Erase all Content and Settings." A prompt will appear, "Erase iPhone," that asks whether you truly want to erase everything. Confirm that you want to. You'll get another prompt, warning that you can't undo your erasure. To ahead and tape "Erase iPhone" again, and it will be wiped clean. Your iPhone or iPad will reboot, and once it starts again, all of your content and personal data will be gone.
How you'll wipe Android depends on what version of Android you have. If you've got a version before Android 4.0, first go to the Home screen and then press the Menu key. From the screen that appears, select Settings --> Privacy --> Factory data reset. A warning screen will appear. Go to the bottom and tap "Reset phone." If you also have an SD card in the phone and want to wipe it, make sure to check the box next to "Erase SD card."
If you've got Android 4.0 or later, go to Settings and tap "Backup and reset." On the screen that appears, tap "Factory data reset." There will be a warning screen. Go ahead and reset, and everything will be wiped.
On the Home screen, tap the Application menu, then select Settings --> System --> About, then tap the "Reset your phone" button. You'll get a warning that resetting your phone will wipe out all of your personal data. Tap Yes. Then you'll get another warning asking "Are you sure you want to erase all of your personal content from your phone." Tap Yes again. Windows Phone will reboot, and it'll wipe all your data.