Discolouration of the knees and elbows can be caused by many natural behaviours. Although it might take a little hard work to resolve the issue, you can get rid of dark brown knees and elbows. There are a variety of home remedies that are highly effective and simple common-sense cures that should do the trick.
Scrub the dark areas thoroughly. The skin on the knees and elbows is usually rougher than the rest of your skin. If you do not scrub it aggressively, it might literally hold on to dirt in the cracks and crevices. Use a loofah and a sugar scrub to really get your knees and elbows clean, then also use the same washing agents to keep them that way.
Exfoliate the darkened areas. If the skin on your knees and elbows has become dark because of pressure, then you might have to remove that skin to get your normal skin tone back. Use a washcloth and exfoliating cream to scrub your elbows and knees no more than twice a week. Do not exfoliate outside of normal washing more than twice a week, or you run the risk of developing chronically dry or itchy skin.
Treat the dark spots with lime juice. Lime juice is a natural bleaching agent and can lighten dark skin. Apply the lime juice to affected areas, and let it sit for 30 minutes. Then wash it off and moisturise the area.
Use sunscreen on your elbows and knees. The sun will tan the skin on your elbows and knees much faster than the rest of your body. Using sunscreen as part of your daily moisturising routine will prevent further darkening and lighten up skin over time.
Modify your behaviour. If you lean on your elbows or spend a lot of time on your knees, they might become darker as a result of the pressure. Try to avoid these postures and behaviours, and moisturise your elbows and knees regularly to help protect them if you cannot avoid these actions.
Combine your lime juice with lemon juice and coconut oil for a really luxurious treatment.