I'm concerned about tweaks that stay on a CDs like the green pen or even sprays. Guess it's because of resale value and unforseen long term damage. I do like the AudioPrism CD Blacklight which is a mat that rests on the CD during play, and then you just take it off. You charge it with light and it glows green and helps with static and CD stability. I don't always use it but it has helped every CD I've tried it on. Particularly older CDs with sub-standard fidelity.
