Like it or not, CDs rot over time -- your well-worn copy of Soundgarden's Superunknown might not play anymore. Just how they rot is frequently a mystery, though, which is why the Library of Congress is currently destroying CDs (including those you donate) in hopes of improving its archival techniques. Researchers are using a combination of artificial aging tests and simple observations to see what factors trigger decay, sometimes with surprising results. As the Library tells The Atlantic, data loss varies widely between manufacturing processes, the lasers in CD players and even individual discs; experimenters can subject two identical copies of an album to extreme heat and lose only one of them.
There are some consistent findings that are useful for both archivists and everyday listeners. You'll want to avoid obvious concerns like high temperatures and scratches, but it's also important to avoid labels and markers -- sorry, that mix CD you burned in 2004 is probably a coaster by now. Recordable discs tend to be more fragile as a rule. The discoveries won't save the CD from becoming yet another obsolete format, but they should make sure that future generations can access digital media from our recent past.
[Image credit: Chris Murphy, Flickr]