Memorex: Explain This, Please...

I had need for CD-Rs and the only brand at the University bookstore was Memorex. I had very bad luck with their 5.25" floppies in the early or mid '80s, but that was a different item a long time ago. The cylinder's wrapping said "Cool Colors." Fine. Like I care. It turns out I do care. Several of the CDs are black. How exactly do I write on those? I don't think it matters what color Sharpie I use, it's not going to show up.