what would i need to do to clear all my private data, apps, settings, etc from my n900 to get it ready for sale? i wasnt sure if flashing, or reflashing, or whatever was necessary or not. i'm a total noob when it comes to all this (mainly why i'm sadly parting with it) so a guide for dummies would be helpful. (i dont know anything about linux, x terminal)

any help would be appreciated.