Two types of discoloration can mar your leather furniture. The first comes from the addition of a stain -- such as a dye, an oil or some other liquid -- and the result is usually darkening of the color. The second type of discoloration involves the removal of the existing finish through wear, with a resulting undesirable lightening in color. You can't always remove stains or satisfactorily repair faded leather, but you can usually make a significant improvement.
General Stain-Cleaning Guidelines
Before you attempt to remove any stain from your leather furniture, you need to know what type of leather it is, because some types, particularly suedes, require specific cleaners. Check the manufacturer's label and recommendations. Another important guideline is to get to the stain when it's fresh whenever possible. The longer you leave a stain, the more likely it is to soak into the leather pores and become permanent. Keep in mind that dyes, such as ink, are virtually impossible to remove once they have seeped under the leather finish, and that can happen in a matter of minutes. You should dab a dye with a clean cloth as soon as you notice the stain.
Water, Grease and Dye Stains
Water and pet urine stains cause a dark discoloration, but more often than not, you can make the discoloration disappear by wetting the entire piece of leather, from seam to seam. Wipe with a wet sponge, and allow the water to soak in. Then apply a leather conditioner to replenish the oils that will leach out as the water evaporates. If the stain is greasy, sprinkle talcum powder on it; wait for 30 minutes or so, and then vacuum it off. To handle other dark stains, including blood, juice or mystery substances, make a paste consisting of 1 part cream of tartar and 1 part lemon juice. Spread this on the stain, and leave it for 10 minutes. Then wipe it off with a wet rag. Follow any stain removal treatment with leather conditioner.
Types of Leather Dyes
Tanners add color to a skin during the leather tanning process by applying an aniline dye, which quickly seeps into the pores and becomes well absorbed. If only aniline dyes are used, the leather is said to be unfinished; leather finishing involves the addition of a pigmented dye -- or colorant -- that remains on the surface. The colorant is a top coat, and it's the dye that's usually most in need of repair. In some cases, you can restore faded color with an aniline dye, but because this type of dye sinks in so deeply, it leaves the leather without a sheen. It's preferable to repair surface discoloration with a colorant.
Applying Leather Colorant
Before applying colorant, prepare the leather -- which is probably cracked -- by sanding it with fine-grain sandpaper to abrade the finish and remove flaking material. Sand and dye the whole piece of furniture -- not just the discolored area -- for the best color matching. Apply a light coat of leather colorant that closely matches the existing leather color, using a sponge; it usually takes two to four applications to complete the job. Allow each coat of colorant to dry before applying the next. Finish off by applying a leather top coat to protect the newly restored leather.