CD other tweaks

Over the week-end, I had the chance to try an audio tweak.. sanding the outside rim of a CD, the impact was great. I have tried the paint route and had some success..but I had heard about using very fine grit sandpaper on the outside rim of a CD. I tried it and it was up there with major component changes. The most hear-able differences were: a more quiet or "blacker" silence between notes..and a sense or more detail..but more ease at the same time. Has anyone else tried this?