I know this sounds random, but I had a hard drive that died awhile back, so I took it apart for fun to see what was inside. In hindsight, that might not have been a good idea, because who know what kinds of nasty chemicals and stuff could have been in there. Anyway, I kept the platters because I thought they looked cool, and I was thinking about using them for coasters. But can anyone here think of a health reason not to do so? According to wikipedia, the platters are made of glass or aluminum disks, coated in 10-20 nm of cobalt, with a layer of carbon for protection. Each of those things sound ok to me, but I thought I would check here anyway.