If you want to lighten the color of wood in your home, bleaching may be the cheapest route. You may want to lighten your floor to prepare it for a special finish, or maybe they have just become discolored with age or spills/stains. The first step in this process is to find what type of bleach will work best for you.
The bleach you will need will depend on the source of the color you are trying to remove. There are three types of bleach you can use on wood: chlorine bleach, peroxide bleaches, and oxalic acid. The hardest part of bleaching your floors is finding out what created the current stain to be able to choose which bleach is appropriate. Chlorine bleach will remove dyes and many stains such as tea, blood, and juices. Household bleach is the mildest form and can take several treatments to see results. Swimming pool chlorine, or calcium hypochlorite can be used for a stronger chlorine-based bleach treatment. Two-part bleach is the only choice for altering actual wood color. Stains that do not respond to either chlorine bleaches will typically disappear when treated with two-part bleaches. Oxalic acid is your best choice to battle iron and rust stains. It can remove water stains and some black inks if they are iron-based. You can find oxalic acid in a crystal form. Any bleach will deteriorate the wood, and those chemically weakened wood fibers can be more susceptible to wear and tear.
Once you’ve found your bleach choice, it is time to start! You will need to strip, bleach and neutralize your hardwood floor. Start by removing whatever is the existing finish. You can use lacquer thinner to dissolve lacquer finishes or denatured alcohol to remove shellac. Paint-and-varnish remover will work on most other finishes. Follow your finish remover with sandpaper to lightly smooth the surface.
Mix a solution of washing soda, found in the laundry aisle of most big stores, with hot water in a small bucket following the package instructions. Use the solution to wash over the now-stripped wood and let air-dry.
Next, you will prepare the bleach you have chosen. Chlorine bleach can be mixed with hot water until saturated. For oxalic acid, use 1 quart of hot water to dissolve about 4 ounces of oxalic acid crystals.. For two-part bleaches, simply follow the product instructions.
Use a synthetic-bristled brush to apply your bleach solution. Natural bristles can dissolve and metal materials can create a chemical reaction with the bleach. Carefully spread an even layer of bleach across the wood and place a paper towel over top to keep it from drying too fast. After 20 to 30 minutes, test the wood color. When the color matches your goal, you can blot up any remaining bleach. Rinse the area with distilled water to rinse away any remaining bleach. You will also need to neutralize the bleached area to completely stop the bleaching action. You can use a blend of half hot water and half white vinegar or a mix of 2 tablespoons of baking soda dissolved per quart of hot water.
Leave your wood to air-dry at least one full day. Sand down any rough areas created by the bleaching. You can coat the wood with a light coat of lacquer to help stiffen the wood and help the sanding. You can now refinish the area as desired. If he stain or color does not lift, you can try successive bleach treatments.
Source: Ladies of Real Estate