For the top, a very good product is made by Raggtop (a cleaner and a protectant). For the plastic window use a cleaner/polish that is made for this purpose (I use a Meguiar's product that is very good). For the chrome, there are specific polishes that should do the trick, I don't think there's anything really special you can do there, either the chrome is good (but maybe dirty) or it is worn. if the latter, not much you can do to make it look better.