Have you tried pulling data from those CD? I tried to pull data from some that have been stored for 15 years and it was hit and miss. Some read ok, some were unreadable.
They were stored in zippered CD storage folders inside my climate controlled house. The pattern of the fabric in the pockets in the folder had been transferred to the CD. Attempts at cleaning the pattern transfer away did not work and the CD remained unreadable.
I was glad at that point that there was nothing on the CD that was not also stored on other more durable media.