When I first started burning cd's I had one disk  I used a Sharpie Fine 
point on and did a lot of writing  all over the disk. Initially it didn't 
seem to hurt the disc. It read fine. After 2 or 3 weeks it couldn't be read. 
Other disks done the same day but with only limited writing, primarily in 
the center area did and still read fine. Suspect the ink ( It was a new 
Sharpie, ink flowed freely) eventually penetrated the disc.
Have switched to Sharpie Extra Fine point with no further problems with 
numerous cd' and dvd's. Writes much clearer and sharper also

FWIW
John Dinges 

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