The tape deck problem could well be the belt which is well worth replacing anyway. You can get new belts from Beoparts but it is important to check which of the two types of tape deck is fitted - this is explained on the Beoparts site. With regard to cleaning the outside, I always fight the temptation to use any chemicals such as Isopropyl Alcohol! I would first dust the unit using a gentle, clean feather duster, plus maybe an air duster (compressed air can) for any groves. Then simply use water and a new, clean microfibre cloth. I use a small spray bottle to spray a very fine water 'mist' over the BeoCenter and then wipe very gently until dry. Don't be tempted to press hard to remove marks - simply repeat the gentle wiping process until they fade.

Thank you for you help, Guy :)