You just bought that shiny new iPhone 5 and told your spouse that you can sell your old iPhone to pay for the new one. I won’t get into the middle of a spousal argument, but I will help you prepare your iPhone for sale.

The goals of this procedure are to:

  • Preserve everything on your iPhone so you can restore it to the new iPhone,
  • Remove your personal information from the iPhone, and
  • Prepare your iPhone so it’s new owner can set it up.

(I assume that you don’t wish to unlock or jailbreak your phone.)

Step 1: Backup your iPhone to iCloud: The easiest way to preserve everything and restore it to your new iPhone is to backup to iCloud.

On the iPhone, go to Settings, iCloud. If you’re not presently signed into iCloud, it will ask you to Sign In. If you share an Apple ID with someone else in your family for iTunes, that’s great, but you probably don’t want to share an iCloud account. You only get 5Gb; that’s just about enough to backup two devices like an iPhone and iPad. You can pay for extra space if you prefer to share accounts.

If you want or need a separate Apple ID for iCloud, tap Get a Free Apple ID.

When you’re ready to backup your iPhone, connect it to a WiFi network, go to Settings, iCloud and scroll to the bottom. Tap Storage & Backup. Enable iCloud Backup and then tap Back Up Now. When complete, go to Step 2 below.

Step 1 Alternative: Backup your iPhone to your computer: If you don’t intend to restore to a new iPhone or otherwise would like to have your backup on your own computer, use iTunes to perform the backup. Connect your iPhone to your computer via USB and start up iTunes.

Step 1a: Transfer your purchases on the iPhone to iTunes. Find the name of your iPhone in about the middle of the left-hand pane in iTunes. It will appear under the DEVICES heading. Right-click your iPhone and select Transfer Purchases.

Step 1b: Sync your iPhone: right-click your iPhone and select Sync.

Step 1c: Backup your iPhone via iTunes. Yes, the sync backed up your iPhone, but I have found that this backup leaves out some crucial data such as the arrangement of your apps and folders. Right-click your iPhone and select Backup.

Step 2: Reset Home Screen Layout:  On your iPhone, go to SettingsGeneralReset. Tap Reset Home Screen Layout. This sets the home screen to factory default layout. Take your photos now for resale because after you erase all content below, you won’t get a home screen. Instead, the phone will display a Welcome screen that lets the new owner set up the iPhone as they wish.

Step 3: Erase all content on your iPhone: On your iPhone, go to Settings, General, Reset. Tap Erase All Content and Settings.

Step 4: You’re done: When your iPhone finishes erasing, it will reboot and show the iPhone Welcome screen. It is now ready for it’s new owner to configure it as they wish.

Step 5: Paranoid erase all content: iPhone 3GS and later use hardware encryption to protect your data. Apple writes that Erase All Content and Settings “erases user settings and information by removing the encryption key that protects the data.” So if their encryption is unbreakable, there is no need to write over the data. Older models do not provide hardware encryption. On those, Erase All Content and Settings overwrites the data. On the other hand, claims have been made that the encryption has been broken.

Depending on what’s on your phone, you might choose to overwrite it yourself. I suggest using iTunes for that since downloading via the USB port is faster than WiFi. I like to sync videos such as from iTunes U that I don’t care if someone forensically discovers. But first, you’ll need to set up the phone as a new iPhone.

Step 5a: Set up as new iPhone: After your iPhone finishes erasing and rebooting, it will show up in iTunes. If you don’t already see the Welcome to Your New iPhone screen, select iPhone under DEVICES. Choose Set up as new iPhone and click Continue and then Get Started. In the Options section of the Summary tab, uncheck all options except Manually manage music and videos. Step 5b: Overwrite iPhone: In iTunes, fill the iPhone with data, then remove it. Repeat up to seven times with different combinations of data in proportion to how paranoid you are.

Step 5c: Erase the iPhone: One last time, on your iPhone, go to SettingsGeneralReset. Tap Erase All Content and Settings.

Step 6: Remove the SIM card: There may be personal data on the SIM card. Remove it.

Optional Step 7: Replace the SIM card: If want to be really nice to your phone’s new owner, replace the SIM card. They’re not expensive. Before you buy one, be sure you know which size it takes.

Step 8: Find all the pieces parts, take your final photos, write your copy, post the ad, profit. Be honest! If at any time you get stuck in the erasing and restoring process and it appears that you’ve bricked your phone, don’t panic. Put the phone into DFU Mode, restore again, and resume where you left off.