I guess my DVD player's lens is getting dirty, so I would like to know: 1. Is a cleaning disc (with brush and fluid) recommended/safe? 2. Are there any other safe way to clean without opening the transport assembly? 3. For a DVD/SACD player, do I need a DVD cleaning disc, or a cleaning CD is also ok? If it matters at all, the model I have is the Sony DVP 9000ES. Thanks in advance for your help.