Hi everyone! I recently purchased a used T100S Yamaha. The salesman told me it was "white brass" so I don't know if that means it's laquered or it has a silver polishing. From what I understand, different finishings require different polishing cloth? In any case, over the few months, the white brass has gradually been turning yellow to the point where it is almost brown! No amount of polishing with the cloth that came with the instrument does any good. How can I restore it to its original white brass shine? Also, the salesman also stated that I don't really need brushes, stating that rinsing is sufficient. Is this true? I'd really appreciate your help!