Not everyone develops black stains on their elbows.
Black stains on your elbows develop for a number of reasons, including years of exposure to UV rays, the development of callouses on your elbows and having hyperpigmented skin---a condition where certain areas of your skin become darker in color than other areas.
Lemon and Lime Remedy
Lemon and lime juices are natural skin lighteners. Squeeze three to four lemons or limes into a small bowl, and apply the juice to your elbows daily after your bath or shower. Leave the juice on your elbows for 15 minutes. Soak a clean towel in hot water, and scrub your elbows. Your elbows will lighten with time. You can also make a cream by combining ½ tsp. of lemon juice and ½ tsp. of glycerin. Apply the cream to your elbows nightly.
Turmeric and Curry Remedy
The herb turmeric can also remove black elbow stains. Mix a paste of 1 tbsp. of turmeric and three curry leaves in a small bowl. Apply the mixture to your elbows and let it sit for 15 minutes. Wash your elbows in warm water. If taking a bath, apply the mixture before you get in, let it sit for 15 minutes, and simply wash it off as you take your bath. You can also use Mehndi leaves in place of curry leaves. Mehndi and curry leaves are found in most international grocery stores and some health food stores.
TIP: Secret tip is to take half piece of lemon and mix few drops of MUSTARD OIL in it. Rub it on your elbows and you'll definitely see the results :)