First of all, you need to keep your elbows clean and devoid of dirt as any dirt that gets accumulated in the elbow region is quite visible and often leads to the darkening of the area. You can use a pumice stone to get rid of dirt. Also, scrubbing the elbow region regularly helps.
To have soft and healthy elbows, you need to keep them moisturized. Always apply coconut oil or olive oil or a moisturizing cream on your elbows after having a bath to prevent drying up of elbows.
If you are suffering from dry and rough elbows, then lemon is the solution for it. You just need to rub a lemon on the elbow region for about 10 minutes and it helps in naturally softening your elbow region.
After that, you should apply a moisturizing cream. The astringent effect of lemon helps in freeing your elbows from rough skin. Thus, lemon is widely used as a natural cure for rough elbows.
If you have dark elbows, then prepare a home made solution for it by adding little almond powder in yogurt. Apply this mixture on your elbows to lighten the dark elbows.