Do you have dark elbows and dark knees? If the skin on your elbows or your knees are relatively darker than your skin you would need to use whitening soap to even it out. Another way to even out the color of your skin is to apply a natural solution, here is what you'd need:
1 tsp dry milk powder
1. Mix all the ingredients together to form a paste.
2. Rub the mixture on your elbows and your knees.
3. Leave it on for 10 to 15 minutes and rinse.
In just three steps you already got a whitening session. You should do this regimen every day for faster results. You should also increase your intake of Vitamin C or fruits and vegetables loaded with the said vitamin so that your skin will look much better. This is not of course the fast lane in the skin department but it will help make your skin look and feel.