Originally Posted by Glenn

Tung oil over older cabinets just sits on the the top of the shellac and will evaporate and will need to be applied again. Since the older cabinets already have a finish on them I recomend you wax them to protect and bring out the shine in the original shellac finish. As always this is a personal choice. I use briwax in clear or brown. I prefer to restore the original finish then try to apply a new finish such as tung oil. Glenn