Spray the furniture with water so it will absorb the wood cleaner and brightener more easily.
Spray the cleaner and brightener onto the furniture with a pump sprayer. Begin spraying at the bottom of the furniture and work your way up to avoid streaking. Allow the cleaner and brightener to seep into the wood for about five minutes.
Scrub the surface of the wood with a stiff scrub brush. Use different-sized brushes if necessary to ensure that you get every surface of the furniture.
Rinse the furniture off with a garden hose, beginning at the top of the furniture and working toward the bottom. Allow the furniture to completely dry.
Sand the furniture with 100 grit sandpaper to level any rough edges from cleaning the surface. Use an orbital sander on the main parts of the furniture, and sand spots that the sander cannot access by hand. Sand in the direction of the grain, and wipe the dust off of the furniture with a tack cloth when you are done.
Apply an exterior grade gel stain to the furniture with smooth, even strokes. Use the applicator that comes with the gel stain on flat surfaces, and a brush for hard-to-reach locations. Allow the gel stain to dry overnight.