I've recently upgraded to the iphone 5 and was going to sell my iphone 3GS. I've gone in and "Reset" and "Erase All Content and Settings" and even connected to itunes to do the factory restore. Can someone still access my personal data if I sell it? I've heard of things like restore apps, etc. I used to have things like the amazon app on my phone and I don't want someone to be able to access my personal data.