How can i Hard Reset or factory Reset Nokia Lumia 520

1. This method, completing all Deleting by all data,
2. So make sure you have not any use all data on your device.
3. First, you must off your Nokia Lumia 520 phones
4. Now simply Press power button after than your phone will vibrate,
5. Then press volume down key until you will see on screen sign of exclamation.
6. After than Just press volume up + volume down + power + volume down
7. Now wait for few second your phone will restart and its done.

Note : This trick lose your all data of your phone