Clean the leather seat with a specialty leather cleaner. Pour the liquid on a chamois cloth and gently work it into the leather in a circular motion. Go over the leather a second time with a fresh cloth, buffing the leather and wiping off any excess cleaner.
Treat rips and tears with the adhesive inside the leather repair kit. Apply the adhesive to one side of the tear and press the other side against the adhesive. Hold the leather pieces together until the adhesive dries and hides the original damage.
Work the leather conditioner around the leather seat with a chamois cloth. Gently buff the conditioner onto the leather in a circular motion. Rub a second cloth over the leather, removing any excess conditioner and bringing back the natural shine of the leather.
Squeeze a small amount of grain filler onto your finger, picking a shade that matches the original color of the plywood. Rub the filler onto any holes or scratches. Once the filler dries, rub 220-grit sandpaper over the filler, until it matches the surrounding wood.
Paint the polyurethane stain on the repaired areas of the plywood, using the sponge brush. Apply a thin coat and once dried, lightly sand with the sandpaper. Add at least three thin layers and sand in between each layer of polyurethane. The stain restores the natural shine of the plywood base.