How to Wipe Your Data Before You Sell, Donate, or Recycle Unwanted Computers and Smartphones
Last updated May 14, 2021
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.
Simply deleting all your files and then emptying the “recycle bin” or “trash” folder doesn’t permanently destroy digital data.
Listen to audio highlights of the story below:
“While 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 that can be viewed typically includes text messages, photos, documents, email, and stored 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.
How to Nuke Stored Data
Before getting rid of that old tablet, laptop, desktop computer, or smartphone, follow the manufacturer’s instructions on how to properly “wipe” the memory. Before you start, make sure any files you want to keep are backed up in the cloud or on 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 ProtectNow.
But that may not be enough to remove all the information on a PC, so it’s a good idea to use a utility program, such as Disk Wipe or DBAN (both free) to 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 in such a way that it could be used to steal your identity,” Siciliano explained.
Consumer Reports has detailed instructions on how to perform a factory reset for Macs, PCs, and Chromebooks.
If the 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. I do that, and it’s very rewarding.
Note: For a device with a solid-state drive (SSD), deleting the files and performing a factory reset is sufficient—no need to dig out your safety goggles and sledgehammer. Once the entire drive has been wiped (by doing a complete reset), deleted data cannot be recovered, according to Chris Hoffman, editor-in-chief of the website How-To Geek.
For smartphones and most tablets, follow these steps:
- Android: Make sure the data is encrypted, perform a factory reset, remove the SIM card, then overwrite the date with an app such as ShredIt – Android (free trial) or AVG Cleaner (free or subscription).
- Apple: Remove and destroy the SIM card. Then destroy any stored data by using the “erase all contents” setting.
The SIM card is either in a side panel or behind the removeable battery, depending on the model—you’ll need to use the end of a small paperclip 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.