Anyone who's bought a lot of used CDs from Japan has probably seen them before--those fuzzy circular things that some people glue to the bottom of their CD trays. But why? My first thought was that they're there to protect the CDs, but after thinking about it some more I realized that that doesn't make any sense at all. There's no possible way the surface of the CD can come into contact with the bottom of the tray.

The only other thing I can think of is that maybe they pull dust off of the CD. Does anyone know what these are really for?

I order cases and stuff from www.bagsunlimited.com and these are in the ordering guide I have. Here's the main description:

"These foam inserts destroy corrosive gasses that may get trapped in cases. Gasses in the atmosphere can easily destroy the thin protective layer on the read side of CD's, destroying data."

Research has showm than CDs CD-Rs, and DVDs are vulnerable to oxidation, corrosive gasses and UV breakdown. This latest discovery is found to help extend the life of the recorded side of a CD and DVDs. Products stored using this technology last 30 times longer than products stored in standard paper sleeves and cases. This technology uses molecular-sized copper fragments to neutralize noxious pollutants that attack and degrade data and protects against eletrostatic discharge (ESD) which can break down the top coat of the CD/DVD an oxidize the inner layer. ESD can comes from simply walking across carpeted floor."

All this aside I think the above isn't a grave a problem as the above makes it out to be. For one, I don't think UV breakdown is much of an issue if you store your originals and use mp3's and dubs of the originals. Additionally, I don't hear of too many older CD's failing at a dramatic rate either.

Personally, I think going to this length to protect your CDs is like going after a fly with a bazooka.

Can't say I've ever seen one in an used item I've bought. As for the whole concept I'd say it makes sense for CD-Rs, those seem to break down fast. I've had CD-Rs break down after 2-3 years and become unreadable (even with low use and good storage techniques). Kindof annoying that I have to periodically backup my backups.

Thanks for that link Ashley, been looking for a good shop that sells CD accessories.

15 years ago we used to buy those cleaner tapes that would clean the head of your tape deck or VCR in the hopes it would last 20+ years...

Now there are products on the market that are touted to help your cds last 300 years instead of 30, but do you think we'll really give a damn about cds by 2025? we've already got 16gb SD cards that are no bigger than your big toenail.

By 2025 we'll probably store our music in our guts, literally. Tapeworms can live just fine in there, so why not make a long storage medium that resembles a flat worm and line it in our intestines? It could easily store 10 terabytes and double as a security system, backing up everything we see by connections with our optic nerves. (Hehe..the consequences of reading Greg Egan...)