Cleaning up sensitive files: How to sanitize storage

“The most common reason for wanting to clean up sensitive files on internal or external storage is when you’re going to sell or give your Mac (or drive) away,” Howard Oakley writes for Eclectic Light Company.
“Before you even think about how to clean these files up, you must know what they contain, and what risk they would pose if someone else were to be able to view them,” Oakley writes. “Governments and large organizations use security classification systems, and you should think in similar terms:”

Files which have national security content.
Any legally-protected information, covered by national data protection law.
Private files.
All other private data which you don’t want others to see (keychains, for example)

“The first two may seem irrelevant to almost everyone, but a lot of business information falls into the second category,” Oakley writes. “However, we’re prone to pretend that it really isn’t that important, until something goes wrong. Here I’m going to concentrate on the latter two, as those are the ones for which you make all the decisions.”
Read more in the full article here.
MacDailyNews Take: This is a great article to read and follow before you give away or hand down a Mac.