Braids and extensions hinder your ability to wash hair thoroughly. Dirt and hair product can build up in the crevices between braids and extensions. There is little you can do to prevent build-up. However, extra care should be taken to clean hair thoroughly once braids or extensions are removed.
Use a shampoo that is specially formulated for clarifying. Clarifying shampoo uses the chemical lauryl sulfate to strip build-up from the roots to the ends of your hair. Generously lather your hair and rinse thoroughly. You can repeat this process two to three times in one sitting. You won't truly be able to tell if your hair is clean until it has been conditioned and dried. If you usually wash your hair every other day or less often, you may want to consider daily washing until you feel that your hair feels clean. Using a salon-quality clarifying shampoo can make the task of deep cleansing your hair much easier. Common store-bought shampoos can often give the illusion of clean hair because they coat each strand of hair with a layer of product that makes it feel smooth. However, these shampoos have been known to cause a build up of hair product that masks the problem. If you spend the extra money on a quality cleaning shampoo, your hair will thank you for it. After wearing extensions or braids, it may take quite a few washes before your hair seems completely clean. Once you are satisfied with how clean your hair feels and appears, discontinue use of the clarifying shampoo. The chemicals in the shampoo can dry out your hair if overused.
Use a deep conditioner. Braids and extensions can leave hair very dry. Conditioner, much like shampoo, does not reach the crevices of your hair when you are wearing extensions or braids. Months without conditioner can leave hair brittle and susceptible to breakage. Also, dry hair is more porous and thus more susceptible to trapping dirt without you even realizing that it's building up. For the first couple of weeks after removing your braids or extensions, use a deep conditioner after every wash. You will notice when your hair begins to return to its normal texture, and as it does, you can reduce how often you use the deep conditioner to prevent hair from becoming greasy.