Traditionally used in France as a furniture polishing oil, 100% pure walnut oil is ideal for use on food-contact items, such as bowls and spoons, both as an original finish and for periodic touch-ups, as it provides a nontoxic finish that will resist water and alcohol. It has a fresh sweet smell and will not give any aftertaste to food, even when coming in contact with freshly wiped bowls or spoons.

Note: Nut oil may affect people with nut allergies, even on a finished product. If reselling a finished product, advise the customer of the finish.

The wood surface to be finished should be completely smooth. Scratches and imperfections are pronounced when finished with walnut oil. The surface should be cleaned and dusted. Since walnut oil may cause some grain-raising, the surface can be moistened, then sanded, to remove any fibers that may stand up once the oil has been applied.

Walnut oil can be applied with a brush, cloth (cheesecloth or other lint-free cloth) or steel wool, or it may be sprayed on. Allow the application to soak in for at least 30 minutes, then wipe off the excess. Allow at least 24 hours between coats. Longer is desirable.

The number of coats required is determined by the end use of the piece. Three or four coats are required for decorative work, whereas six or more are required for heavy-use items such as foodcontact utensils.

Walnut oil should be applied pure for all food-contact applications. For other uses, the first coat can be cut with mineral spirits at 50%, as it will penetrate much better than pure walnut oil and will dry in about half the time.

Walnut oil can also be heated to accelerate its drying time. Heat in a pot less than one-third full until fumes appear. Like any oil, if overheated it becomes flammable.

Caution: Walnut oil cut with a drier (e.g., mineral spirits) should not be heated.

A top coat can be applied over walnut oil, but the oil should be allowed to cure for three to six months before any top coat is applied. Humid or cool conditions will lengthen this time.

Walnut oil should be stored in an airtight container that protects it from light. Light and air cause the oil to cure. Collapsible bottles are ideal for storage. If you wish to keep the oil stored in its original can, add marbles or clean rocks to eliminate air space and prevent air from curing the oil inside the can.
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Caution: Rags that have been used with waxes or tung, linseed or other oils should either be hung in the open air to dry thoroughly, or be sealed in a fireproof, airtight container. Their tendency to spontaneous combustion has allowed them to burn the workshops of the unwary.