Our digital devices are doomed to die or become obsolete. As I recently reported, because electronics contain a terrible mix of toxic chemicals and materials, you should dispose of them properly. But before doing that (or donating or reselling them), you’ll need to make sure you’ve “wiped” the memory completely.

It's not enough to simply delete all your files; that usually won't permanently destroy digital data.

Listen to audio highlights of the story below:


“We are led to believe deleting makes things permanently go away; the truth is that data can be retrieved in most cases,” said Chester Wisniewski, a principal research scientist at Sophos, a global security company. “Not just police or forensic experts can access deleted data; the tools are available to almost anyone, including identity thieves and nosy second or third owners. The sensitive data includes text messages, photos, documents, email, and passwords.”

The good news is that if you accidentally delete something or if you have a device failure, you usually can still retrieve lost files. This article from Checkbook explains how to do that.

Before getting rid of an old tablet, laptop, desktop computer, or smartphone, follow the manufacturer’s instructions on how to properly “wipe” the memory.

Before starting, back up any files you want to keep to the cloud or another hard drive.

“You want to bring that device back to factory settings, and that means reinstalling the operating system,” said Robert Siciliano, a digital security expert with Protect Now, a cybersecurity consulting firm.

For desktops and laptops, here are links to manufacturers' instructions on how to do that:

Doing a total reset on a PC still may not remove all your info and files; afterward, it’s a good idea to run a utility program, such as Disk Wipe or DBAN. Both of these free apps will destroy whatever data is left on the drive.

“These utility programs are designed to nuke, or overwrite, all the leftover data so that it’s indecipherable and really can’t be put back together to steal your identity,” Siciliano explained.

If your old device contains extremely sensitive data, or you just want to be extra careful, you may want to remove the hard drive and physically destroy it. A few good whacks with a hammer or a couple of holes drilled through the disc will do the trick. If you’ve been having trouble with your computer, you’ll find this task is very rewarding. If your device has a solid-state drive, deleting the files and performing a factory reset is sufficient—no need for safety goggles and a sledgehammer.

For smartphones and most tablets, follow these steps to delete your files and reset them:

  • Android—Make sure the data is encrypted by going to “Settings,” then “Security,” then “Security & Location,” then “Encryption & Credentials,” and, finally, “Encrypt Phone” if it’s not already encrypted. Then perform a factory reset by going to “System,” then “Reset Options,” and then select to “Erase All Data.” Remove the SIM card and then overwrite any remaining data with an app available from Google Play such as ShredIt (seven-day free trial) or AVG Cleaner (free or subscription).
  • Apple—Remove and destroy the SIM card. Then go to “Settings,” then “General,” and then choose to “Erase All Contents and Settings.”

You can locate the SIM card either in a side panel or behind a removeable battery, depending on your model. You’ll usually need to use the end of a small paper clip to pop open the drawer.


Contributing editor Herb Weisbaum (“The ConsumerMan”) is an Emmy award-winning broadcaster and one of America's top consumer experts. He is also the consumer reporter for KOMO radio in Seattle. You can also find him on Facebook, Twitter, and at ConsumerMan.com.