We really need more details. Are you speaking about an old acrylic laquer finish ? If so ... just put a polish there. Something like Nufinish will probably last a long time.
If you have managed to buff up base coat (as the clear has broken down) nothing other than a repaint will fix this. modern urethanes really don't need any "coatings" to protect them. The crap they sell iwth new cars is just snake oil to drive up profits.
seeya,
shane L.
PS: My idea of detailing a car is parking it in the rain ..... or drive it at speed through the puddle with least mud in it :wasntme:

