I am finally going to sell my trusted 770 and upgrade to a newer model.

But before I do I would like to erase all of the data (settings, documents, history, everything!) from the machine.

I am not letting go of my memory card so thats no problem, its just the devices storage.

Is it safe enough to simply re-flash the device? or do I need to shred some stuff first??

Im not super paraniod or anything, but the recent batch of iphone-not-erased-properly headlines make me think I need to be sure!

Sorry if this has been covered before, I did some searches but came up blank.
Thanks,,