Apple’s newest smartphone, the iPhone X, was released Friday and hundreds of people lined up at local Apple stores to purchase it.

Many who bought the phone will use it to replace their previous smartphone devices. But before they throw those old devices away, experts say that they should clear them of any and all personal data.

“If you delete files, there’s still data floating around in there,” says Consumer Reports technology writer Bree Fowler. “Before you sell your phone, you really need to wipe it and get all your personal information off.”

iPhone users should back everything up, sign out of iTunes and iCloud and then do a factory reset. This will erase the phone’s data. iPhones are encrypted, so this should be enough to prevent anyone from accessing personal information.

Consumer experts advise Android device users to go into their phone’s settings and encrypt them before doing the factory reset.

Anyone who is throwing out an old computer is also advised to take precautions to protect their data. Most computers don't have fully encrypted hard drives, which means even if files are deleted, someone can recover them.

It is possible to buy software to overwrite old files, but Fowler prefers a simpler approach.

“The best thing to do, especially if you're going to e-cycle it…take a power drill and just put a hole through it…destroy it,” she says.

The new iPhone X has a price tag of $999.