hi i bought an iPhone4 last week and therefore will be selling my trusted (but slow!) 3G. i installed a clean OS on it (actually, i downgraded the OS from 4.2.something to 3.1.something. iOS 4 on a 3G wasn't spectacular in terms of battery lift and speed) is there anything else i need to do so as to make my old data inaccessible? thanks in advance alexandre