lowrider57 ...
I've tried a bunch of the after-market CD treatments. While some appear to "make the sound of digital sound more analog," by smoothing the sound, I've found that they remove some high frequencies. That's why I switched to a basic eyeglass lens cleaner. After cleaning, I use a Radio Shack DVD tape eraser to demagnetize the CD.
I think it best to seek out recordings that were engineered correctly. If done properly, Redbook CD's sound amazing.
Frank