How To Use HAIR CARE For extra moisturization, add Jamaican Mango & Lime® Jamaican Black Castor Oil – Xtra Dark to your Leave-In Conditioner. Shake well. Use as directed. EYELASHES Dip clean mascara wand into Jamaican Mango & Lime® Jamaican Black Castor Oil – Xtra Dark. Shake off excess oil from wand. Apply the oil to top and bottom lash line. Leave on overnight and remove in the morning. EDGE CARE Using the tip of a finger, massage the Jamaican Mango & Lime® Jamaican Black Castor Oil – Xtra Dark along the hair’s edge line. Repeat as needed.