If you buy a new phone, or otherwise want to dispose of your phone, Nokia recommends that you recycle your phone. Beforehand, remove all personal information and content from your phone.
Remove all content
Back up the content you want to keep to a compatible computer.
Close all active connections and calls.
Select > Settings and Phone > Phone management > Factory settings > Delete data and restore.
If prompted, enter the security code.
Your phone switches off and then on again. Check carefully that all your personal content, such as contacts, pictures, music, videos, notes, messages, mails, presentations, games and other installed applications have been removed.
Content and information stored on the SIM card is not removed.
Remember to remove your SIM card from the phone.