Can you still replace CD lenses in CD players when they go bad? I remember my dad doing this for me a long time ago, but I don't know if it is worth doing now. I've had my player for along time and I think it's on it's way out.
Have you tried a CD/DVD disk cleaner (the one with a micro brush) for the lens? I'm not sure about using liquid because I'm afraid it will cloud the lens, though. But if the player is really old, maybe it's time to get a new one? Sometimes maintenance costs more than buying a new one.
I know absolutely nothing about maintaining CD players, so I would just buy a new one. If you do, look up the preventative maintenance suggestions and do those with the new player.