Photo: Brieuc Daniel

The Library Of Congress wants your old CDs. The reference material clearinghouse is currently soliciting CDs—both burned and commercially issued—for experiments on how quickly material on the discs degrades. Fenella France, Chief of Preservation Research for the Library, told The Atlantic that she and her colleagues are experimenting with the CDs in order to learn how to save them. Apparently, CD manufacturers have changed their processes over the years, but they won’t say how, leaving archivists like France wondering how different types of discs hold up against heat, cold, and age.

The Atlantic’s piece has more detailed descriptions of some of France’s experiments, but their findings essentially break down to this: Even CDs made by the same company within the same year and wrapped in identical packaging could have completely different life spans. And though there are some general rules—like, “leaving CDs in the car in the summer will ruin them”—figuring out how to preserve them has been more or less a total crapshoot so far. It is known that discs with labels or writing on the top will go through chemical reactions that make them degrade faster, so keep those mix-CD love notes on the jewel case.