How to Factory Reset your Android Phone
If you are the unlucky guy who happened to forget the unlock password on your Android, the method introduced above won’t help at all. Since you can’t access the phone, factory reset your device in Recovery Mode is the ideal way for you now.
Simply turn off your device. Then press some certain buttons combined, like “Power” + “Volume –“, or “Home” + “Back“, to enter Recovery Mode. Select “Wipe date/factory reset” in the option menu thus your Android is in the factory reset process.
Note: Compared to the above two methods, wipe data under Recovery Mode is more thorough than that in Factory Data Reset operation. Plus, factory reset under Recovery Mode also means all the content in the device is permanently wiped out.