Hard Reset NOKIA 6270

Turn on the device.
From the Home screen tap Menu -> Settings -> Restore Factory Settings.
When is promted to enter security code, then enter that.
* The default code is: 12345
In the end your phone will reset and reboots.

Remove Lock Code in Nokia Phone - factory reset with forgotten security code

WARNING !
Hard Reset will erase all of your data
All described operations you are doing at your own risk.