Long-term CDR storage

For testing a external USB DVD-burner I needed "something" to test it with. That brought me to 2 packs of CDR-blanks that have been laying around here for ages, I think they have been bought when my trusty old Yamaha CRW4416 x4-Burner I'm using until now was new. That makes them about 5 years old? Well... those CDR blanks were still in their original packaging, with the plastic foil intact. But they looked quite interesting, with a dull finishing and something that reminds me of frosted glass-windows.