[George]

I had the same problem a few months ago and called Plextor.

They got very upset regarding using a CD type cleaner. They said one should never use anything that comes in physical contact with the laser lens, and suggested I buy a can of compressed air.

That's what I've used ever since. If you do the same, don't linger with long blasts of air. A few short blasts are not as apt to have a super cooling effect.

Just passing on what their tech support had to say.

Hope this helps.

George