Thanks for your response Davehrab. I can only see one of the rails, and I tried to wipe it. That attempt was not helpful. I tend to think that since this CDP stayed in the shop of the authorized service person for some weeks (and he said, "the player is not skipping here in my shop," and I got the CDP back; perhaps, that service person should have wiped those rails, since he charged me more than $165 for his service, plus shipping. Maybe, he did not, I am not sure. (I live in a small town in central Illinois, and there are not much of electronics shops who can de-install something if necessary and lubricate those rails for me; I knocked every possible door in my town.) When one pays so much $$$ at the beginning for such a CDP, it becomes quite hard to discard it.