Oil from the tung nut is valuable for most refinishing because it dries to a durable, invisible film that is resistant to penetration by water, alcohol and acids.

Because of this drying property, a tung oil finish on wood is virtually impervious to spills of alcoholic beverages, fruit juices and water spots from cold glasses. It is also heat-resistant.

Tung oil also makes for a good finish on metal. Lacquer, for example, is the conventional finish for brass. But lacquer will darken with age, and the brass will tarnish under the lacquer.

Here's how to apply tung oil to brass: After the old lacquer has been removed (soaking in a strong solution of an all-purpose liquid clearer usually does it) and the brass is cleaned, heat the metal slightly. Small pieces such as brass furniture polls can be placed on a tray and warmed in an oven at low heat for approximately 20 minutes. Larger pieces can be placed in direct sunlight for an hour.

After the brass is warm, small pieces can be dipped in the tung oil and hung to dry for four hours. On large pieces, tung oil can be applied with a soft cotton rag. Apply a thorough coat, let it set for 15 minutes, then buff off excess oil with a soft cloth. Let dry for at least four hours.

After the brass is polished and before the tung oil is applied, be careful not to touch the metal with bare fingers because skin oil will interfere with the drying of the tung oil. Wear rubber plastic gloves when handling the brass.