We do a lot with our phones these days, from keeping in touch with friends and family to banking and working, so it’s a good idea to make sure as little data is recoverable from your smartphone as possible.
For most people who are simply passing their old phone on to a family member or trusted friend, a simple factory reset will be enough to wipe your data and stop people having access to it.
If there is sensitive data on your phone that you would rather no one saw – embarrassing photographs, confidential business plans, nuclear specs, national security files – the only way to be 100 per cent sure that no one will ever recover your data is to smash the phone into little tiny pieces and scatter those pieces in many different locations.
But that is neither practical nor ecologically sound, and it’s a waste of a good smartphone – more on what to do with your old tech later in the week – so your best best is to wipe your phone as thoroughly as you can.
Android:
First, remove your sim card and memory card if there is one in the phone. You can leave the phone connected to wifi if needed.
For older Android phones (under Android 4), go to settings>privacy>factory data reset, and select reset.
For Android phones running Lollipop or newer, go to settings>backup and reset>factory data reset. Click erase everything.
For the newest version of Android, Android Pie, you'll need to open the Settings app, go to system>advanced>reset options. Then choose Erase all data.
In some cases though, you will have to remove your accounts before performing the factory data reset. If you have the newest versions of Android – Marshmallow (5.0) and above – go to settings>accounts and tap your Google account. Select your Google email address, then tap the menu icon and remove account. Then you can perform the reset through settings>backup and reset>factory data reset. Click erase everything.
Regardless of what version of Android you are using, to make sure your devices have no access to your Google account, go to myaccount.google.com/ security, and click on device activity & notifications. You’ll see a list of devices there with the last time they accessed your account. Select the one you want to remove and click remove.
If you need something a bit more robust, you can encrypt your phone. Although there are drawbacks to that, it will make it more difficult to recover data from it afterwards.
iOS:
If you are using iOS 10, you should sign out of your iCloud account before trying to reset your phone to deactivate the activation lock.
To wipe your iPhone, got to settings>general>reset. Then tap erase all content and settings>erase iPhone. You’ll have to confirm you want to erase your phone, then enter your passcode if prompted.
If you have an iPhone with iOS 9 or under, you may be prompted to enter your password when Apple ID.
