What to do with your old Android phone before selling it

[johnypowas]

How to wipe your phone or tablet before you sell it

Trading in or selling your old mobile device? Wipe it the right way to reduce the risk of personal data falling into the wrong hands.
Remember that no method apart from physically destroying the device and its storage is 100 percent foolproof -- data may still be recoverable with the right tools.
These tips are for the three main mobile operating systems, but if you have an older phone or an alternate OS, check the manual for full details on how to wipe your device.
Before you start:

• Back up all your data, including contacts.
  
• Remember to remove the SIM card and any external storage such as a microSD card.
  
• Log out of services like email and social media, then clear the data from these apps if you can.
  
• Perform a separate encryption and wipe of data on the microSD card as well if you don't plan to use the card in a new device.
  
• Keep the serial number of the phone or tablet on file for your records.