If you've ever wondered how to be sure some crook can't steal the information stored on your personal computer when you get rid of it, federal officials recommend "pounding with a hammer."
The idea is to "disfigure, bend, mangle, or otherwise mutilate the hard drive so that it cannot be reinserted into a functioning computer," according to the Commerce Department's National Institute of Standards and Technology in its "Guidelines for Media Sanitization."
The advice might seem peculiar in this tech-savvy age. But it reflects a fundamental problem people face when discarding their computers and smartphones. Other methods commonly used to eliminate stored bank records, Social Security numbers, and other confidential data can't always be counted on to work, experts warn.
"Ultimately it does mean the consumer has to do their due diligence," when disposing of such devices, said Mark Oldfield, communications director for California's Department of Resources Recycling and Recovery, which promotes the reuse of electronic and other items.
Removing sensitive files from computing devices -- a process called "clearing" -- is crucial. If done improperly, criminals can still steal information such as the owner's identity and financial records. Two MIT graduate students several years ago reported finding scores of credit card numbers, medical records, email and other personal records in hard drives bought through eBay (EBAY) and other sources.
Because simply hitting your computer's delete button won't eliminate what's stored on its drive, one popular alternative is to use special software that wipes the information clean by writing over it with random data. Microsoft recommends Active@KillDisk or Softpedia DP Wiper software, which can be freely downloaded.
However, that approach isn't foolproof, according to the federal Homeland Security Department's U.S. Computer Emergency Readiness Team.
"While experts agree on the use of random data, they disagree on how many times you should overwrite to be safe," it warned in a report on disposing of computing devices. "While some say that one time is enough, others recommend at least three times."
Consequently, it agreed with the idea that "physical destruction is the ultimate way to prevent others from retrieving your information."
Choosing the best way to do that, however, can be problematic.
Although some businesses destroy data on tapes and hard drives by exposing them to a powerful magnet -- a process called degaussing -- that's often too expensive for individuals.
Other methods are to melt, pulverize or shred the computers. But experts warn that not all companies offering such services can be trusted to destroy the gadget's data. Similarly, they caution against assuming the information will be obliterated by every place that accepts electronic gear for recycling.
"As a collector, we just intake the computer parts," said Greg Sanborn of Tri-CED Community Recycling in Union City. He added that Tri-CED then sends the machines to other recyclers, but he wasn't sure how they deal with the hard drive's contents.
People also should be careful about shipping their old phones to companies offering money for the gadgets, said Robert Johnson, CEO of the National Association for Information Destruction, which represents businesses that eliminate computer data.
"If you are sending them off to be reused to one of these websites," he said, in many cases, "you have no idea what the fate of it is."
But don't despair. You can always take matters into your own hands.
"It is possible for you to destroy your hard drive by drilling nails or holes into the device yourself or even smashing it with a hammer," according to the government's Computer Emergency Team, though it cautions that it's unwise to "burn a hard drive, put it in the microwave or pour acid on it."
The National Institute of Standards and Technology has another tip. Anyone bashing their PC to bits, it notes, should consider "wearing appropriate safety equipment."
Contact Steve Johnson at firstname.lastname@example.org or 408-920-5043. Follow him at Twitter.com/steveatmercnews
Removing SENSITIVE data
These are among the most common methods for expunging information safely and securely from a computer's hard drive: