In order to hard reset a Nokia Asha 309, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Nokia Asha 309 device will be brought back to the default configuration of a brand new device.
1. Press & hold the Power button until the device turns off.
2. Now press & hold * + Power + Call + 3 buttons until the Nokia logo appears on-screen.
3. Press Call button to confirm the hard reset process.
4. Voila, done.