Moisten a sponge or clean, soft cloth with water. Squeeze out any excess water. Wipe the surface of the wood to remove dirt and grime. In most cases, this is all that needs to be done to a tung oil finish to keep it clean. You should wipe the finish regularly to keep dirt and grime from building up on the wood surface.
Mix together 1 cup boiled linseed oil, 1/4-cup of white vinegar and 1 cup of turpentine. Dip a clean, soft cloth into the cleaning solution and apply the cleaner to the tung oil finish. Let the solution stand on the surface for several minutes to loosen dirt and grime. Wipe off the excess solution with a second cloth. Do not allow the solution to remain on the surface for a long time as it will become sticky and attract dust.
Avoid putting household dusting waxes and polishes on a tung oil finish. Instead, clean with a soft, damp cloth or feather or mirco-fiber duster to remove dust and dirt during regular cleaning. Twice yearly, you should apply a thin layer of tung oil to the finish. Not only will this bring back the luster of the wood, it will help to protect the finish from spills and grime buildup. To do this, mix equal parts of tongue oil and mineral spirits in a small bowl. Dip a clean cloth into the mixture and smooth evenly on the surface of the piece. Both tung oil and mineral spirits are available at most hardware stores and home improvement centers.
Always purchase pure tung oil for applying to a surface with a tung oil finish. Many of the products on the market are made with other ingredients that could harm the finish if applied. Read the label of the product to insure that it is 100 percent pure tung oil.