*#7370# — Completely wipes all data and restores the phone to its original brand-new state.
*#92702689# (which spells *#WAR0ANTY# )
Wipes all data and returns the phone to a brand-new state. and back up data first. *#92702689# Warranty/Life Timer How to Use Secret Codes on NOKIA 106
*#0673# (for Audio test)