The new Apple iPhone 6s and iPhone 6s Plus go on sale Friday, September 25. You may be one of the millions who have already pre-ordered their new iPhone 6s, or you may still be trying to decide if the new iPhone is for you. Either way, unless you are lucky enough to have an upgrade due on your carrier contract, you may first have to sell your old iPhone before you can splurge on a new one.

Your iPhone contains a lot of personal information about you, including contacts, photos, security data, banking info, and more. Before selling your iPhone, it’s a good idea to make sure you prevent this sensitive information from ending up in the wrong hands.

We’ve created the below guide to help make sure your info is safely and completely removed from your old iPhone and ready to be restored on your new iPhone 6s. There’s also a tip or two to make sure you have a happy buyer. (Be sure to check out the links at the end for help selling your iPhone.)

Back up your data via iTunes or iCloud

You’ll want all you current data on your shiny new iPhone, so create a backup of your old iPhone before erasing the content and settings (step 4) and selling it.

To back up your iPhone via iTunes on Mac or PC, make sure you have the latest version of iTunes installed, and then connect your iPhone to your computer. In iTunes, go to File > Devices > Back Up and follow the instructions. Double check that the backup ran by going to Preferences > Devices > and check that the date and time on the last backup correspond to when you ran this backup.

To back up your iPhone via iCloud, go to Settings > General > iCloud Backup > Back Up Now. If you have iCloud Backup toggled on, it will automatically back up photos, accounts, documents, HealthKit and HomeKit data and settings while your iPhone is plugged in, locked, and connected to Wi-Fi.

Deactivate Find My iPhone

In some cases leaving Find My iPhone activated on an iPhone can prevent the new owner from activating the iPhone in his/her name. It is good practice and considerate to deactivate Find My iPhone before cashing in on the sale. Go to Settings > iCloud > Find My iPhone and toggle it to Off.

Sign out of all other accounts

While erasing all content and settings from a device will remove all apps and require that they be reinstalled and login credentials re-entered, it does not hurt to sign out of individual accounts – especially if you are also signed in via the web and not just an app.

Consider signing out of accounts/apps like Twitter, Facebook, Instagram, Gmail, Skype, YouTube, or any others you stay logged into.

Erase all content and settings

This step is the main one and should prevent any unwanted data tagging along with your iPhone when you sell it.

First, sign out of your iCloud account by selecting > Settings > iCloud > Sign Out. Do not skip this step as you’ll end up erasing the backup you created in iCloud earlier.

Next, go to Settings > General > Reset > Erase All Content and Settings. You may be required to enter your passcode and Apple ID password.

Note: Make sure your phone is plugged in and charging as it may take some time for all your content and settings to be deleted.

Remove your SIM card

Unless your SIM card is part of the sale for some reason, you’ll want to remove it from your iPhone before handing it over to the new owner. Your SIM card contains your phone number, some security data, billing info, and more. It’s never a good idea to just hand over personal data like this.

Locate the SIM ejector on your iPhone and pop it out using a paperclip. The SIM card slot is not in the same place on all iPhones. Locate your model iPhone’s SIM slot using the below chart.

How t remove the SIM card from iPhone via Apple.com

Clean your iPhone and organize accessories

A clean iPhone in a good condition will fetch you a better second-hand price than a ratty looking phone covered in scratches, fingerprints, and dust.

Turn off your iPhone, unplug all cables and accessories and remove dust from inside the ports and clean the casing and screen with a soft, lint-free cloth.

Last, but not least, make sure you have your iPhone’s charger, cables and any other accessories listed as part of the deal on hand when you hand over the phone to your buyer.

If you need some help selling your old iPhone, check our handy guides below:

How to sell you iPhone on eBay

Where to sell your old iPhone and what it’s worth

Top dollar for old iPhones: Gazelle promises best trade-in value

Sources: PC Mag; iMobie; iGeeksBlog

Image credit: Dennis Yang via Flickr