Jailbreak / Restore Question

Hey all, I have a quick question.

Long story short, I have a few brand new iPhones that I'm going to be selling when my Gevey SIM's come in. They are both on 4.3.2 and I jailbroke one of them using redsn0w and the OEM .ipsw and selected 'Install Cydia'.

Which method is best to remove the jailbreak from the phone so it basically looks like new and unmodified?

If I hit 'erase all content' from the menu, will that remove the jailbreak or do I need to restore it using the stock .ipsw via iTunes?

Thanks all!

 

They are the new Gevey Plus that is the untethered version and I will use that with the sale. I waited until that one was available and they should be arriving this coming week. When I sell a phone, I include a SIM cutter w/ the phone. You can buy them in bulk for $5 a piece and they work well.

Thanks for the info.. I just wanted to restore the jailbroken phone back to stock before I sold it.