Watco? Danish oil is a blend of penetrating oil and varnish that hardens in the wood, not on the wood surface. Watco? danish oil penetrates deep into wood pores to protect from within and to enhance the natural look of the wood. It creates a rich color of a traditional hand-rubbed finish. Many projects can be completed in less than an hour. Danish oil is easy to use. Simply brush or wipe on and wipe off.