I just tried doing the CD-test with my waffle weave and bonus green MF from Rob.
I rubbed the green MF pretty hard on my blank cd and there was no visible marring. I made sure to view the cd from about a million different angles and could not find a single scratch.
With the waffle weave, i noticed a few VERY light scratches after rubbing the cd with moderate pressure. I'm sure it would not do any damage under the usual light pressure / blotting technique i use when drying.
I am completely satisifed with these products and to top it off, Rob's customer service is some of the best I have ever encountered.