Well, I have experimented and I think the best approach is to always keep you CD's clean, so that nothing is transferred to the lens while the disc is playing
I have found that cleaning the CD with a soft tissue and metho is sufficient, then discard the tissue after cleaning the disc, along with the occasional use of the Lens cleaning disc... perhaps once every 1 or 2 months
I have tried VuPlex and I really do not like it unless it is used for repairing a scratched disc that you are trying to copy