While it may be beautiful in an unsophisticated manner, pine is also soft and vulnerable to damage. Ink splotches, water spots, stains from grease, oil or food, even naturally occurring color variations may disfigure the pine's appearance, turning a pleasing-to-the-eye pine finish into an eyesore. Whether you want to even out the color or remove a stain that's soaked into the wood, applying a bleach treatment is the answer. There are three common bleaching products for this job: choose only one method, based on the type of lightening you require. If the wood is already finished, first remove the finish and clean the wood before applying your chosen bleach treatment.
Prepare the work area. Cover any vulnerable areas or items, such as carpeting and furniture, with plastic sheeting to protect it from harm during the bleaching process. Open windows and turn on ceiling fans or a portable fan to create ventilation.
Strip the pine's existing finish, if present. Choose lacquer thinner to dissolve lacquer finishes (typically used for modern wood finishes); denatured alcohol for shellac finishes. If neither seems to soften the finish, use a commercial paint-and-varnish removal product. Soak disposable rags or thick layers of paper towels in the solution and lay them across the pine, when possible. Alternatively, brush the solution onto the wood. Wait the recommended time period, then reapply as needed to allow the remover to soak into the finish as much as possible. Wipe away the finish as it softens. Remove stubborn finishes with reapplication or by scraping with a plastic spatula or scraper. Avoid gouging the wood.
Mix a small bucket of hot water with a dash of washing soda -- sometimes referred to as sal soda. Allow the powder to dissolve briefly. Use the amount suggested in the product instructions. Wash the wood with a fresh cloth and the cleaning solution to remove the stripping chemicals, any remaining finish, dirt or oils. Scrub gently with steel wool and wash again if any finish or contaminants remain. Allow the wood to air-dry completely.
Use laundry bleach to remove food stains or lighten existing dye-based wood stain on the pine: Pour regular laundry bleach into a glass jar. Apply the bleach to the pine, using a paintbrush. Reapply the bleach every few minutes or as necessary to ensure the wood stays damp. Work in small areas to prevent the bleach from soaking in prematurely, if necessary. Wait 20 to 30 minutes, then neutralize the bleach with a rinse consisting of equal parts vinegar and hot water. Repeat, once the wood is completely dry, if further lightening is desired.
Use a two-part bleach if you want to strip the natural coloring from the wood fibers and to partially lighten pigment-based wood stain (two-part bleach does not lighten dye-based stain): Mix equal measures of sodium hydroxide and hydrogen peroxide -- components of a two-part bleach -- in a plastic or glass container as directed by the product manufacturer. Apply with a sponge or synthetic brush, leaving a generous coating on the wood. Wait until the color matches the shade desired, then neutralize with a solution of equal parts vinegar and hot water. Let the wood dry to check the results. Repeat the bleach treatment as necessary for further lightening.
Use oxalic acid to "brighten" weather-aged wood, as well as to remove black water spots and rust stains: Dissolve oxalic acid crystals into 1 gallon of very hot water, following the manufacturer's instructions to determine the mixture strength. Weather stains and sap streaks require approximately 8 ounces of crystals to 2 quarts of water, creating a super-strength bleach. Brush the solution onto the wood with an old paintbrush, leaving a generous coating. Allow the bleach to dry before checking the color. Reapply as many times as necessary to achieve the desired result. Neutralize the acid with a wash of baking soda and water mixed at the rate of 2 tablespoons of baking soda to 1 quart hot water.
Sand all bleached pine once the wood has completely dried. Use fine-grit sandpaper to remove furry woodgrain and smooth the surface. Alternatively, apply a very thin coating of shellac to stiffen the raised fibers in the wood. Allow it to dry, then sand the pine. This works best if the wood is extremely fuzzy. The water used during the bleaching process typically raises woodgrain and causes this problem.