This will make a basic clean..if your lens need a deep clean you will have to open the drive and clean the lens with cotton swab wet with good quality isopropyl alcohol. Hope this help you. sorry about english.
First, clean the lens. For the one read CD but not DVD, I think you should upgrade the firmware of the drive, be carefully if you do it wrong, it will go to trash.
actually isopropyl can destroy lens.. I would use just cotton swab in your place and about drive which reads cds but not dvds - seems to be dead.