In order to hard reset a BLU Tango, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
BLU Tango device will be brought back to the default configuration of a brand new device.
1. Turn on the phone.
2. Open Menu and go to Settings -> Privacy -> Factory Data Reset -> Reset phone.
3. Information windows will appear, accept them all. Complete, the hard reset is done.