Restoring iPhone for Sale.

[NbinHD]

Ok, I sold my iPhone 4. Awesome. $275 and alright condition. So if I do a restore from the phone itself, can i be assured that my information is gone for ever and not retrievable?

 

[KandyKane]

Turn off iMessages first, otherwise it gets stuck! You might want to sign out of your Apple ID to be safe.
Then wipe it.

 

[Macman45]

Wipe it via settings / general reset, taking care to remove the sim (if any) and leave it at the setup screen.

I've done it several times without any problems at all...Sold my 4S a few weeks back and that's how I did it.

 

[iPhone1]

Turn off iMessage, log out of Apple ID, make a backup if you're switching to another iPhone, restore in iTunes to latest firmware. Eject from iTunes before it prompts you to use as a new phone or restore from backup. Remove SIM card.