You may own tools that will last your lifetime, but the same can't be said of the finishes in your cabinet. When you purchase a finish, the clock starts ticking. And it ticks even faster when you open that finish, or mix your own, and use some of it. Finishing expert Jeff Jewitt shows you how to maximize the shelf life of your finishing materials, whether you are using oils, shellac, polyurethane, or something else. (Often—but not always—the secret lies in keeping oxygen out.) Learn this tip and others, and you'll avoid wasting time and money on a finish that has gone past its shelf life.