Hugh Pickens DOT Com writes: Adrienne LaFrance reports at the Atlantic that for people of a certain age, if you've tried listening to any of the old CDs lately from your carefully assembled collection from the 1980's or 1990's you may have noticed that many of them won't play won't play. "While most of the studio-manufactured albums I bought still play, there's really no telling how much longer they will. My once-treasured CD collection—so carefully assembled over the course of about a decade beginning in 1994—isn't just aging; it's dying. And so is yours." Fenella France, chief of preservation research and testing at the Library of Congress is trying to figure out how CDs age so that we can better understand how to save them. But it's a tricky business, in large part because manufacturers have changed their processes over the years and even CDs made by the same company in the same year and wrapped in identical packaging might have totally different lifespans. "We're trying to predict, in terms of collections, which of the types of CDs are the discs most at risk," says France. "The problem is, different manufacturers have different formulations so it's quite complex in trying to figure out what exactly is happening because they've changed the formulation along the way and it's proprietary information." There are all kinds of forces that accelerate CD aging in real time. Eventually, many discs show signs of edge rot, which happens as oxygen seeps through a disc's layers. Some CDs begin a deterioration process called bronzing, which is corrosion that worsens with exposure to various pollutants. The lasers in devices used to burn or even play a CD can also affect its longevity. "The ubiquity of a once dominant media is again receding. Like most of the technology we leave behind, CDs are are being forgotten slowly," concludes LaFrance. "We stop using old formats little by little. They stop working. We stop replacing them. And, before long, they're gone."