D.I.Y. Hair Treatment Avocado + Egg + Lemon Combine 1 avocado, 1 egg and a very small amount of lemon juice until mixed well. Apply the mixture to damp hair and leave on for about 20 minutes. Rinse hair with luke warm water—hot water could cook the egg leaving a huge mess! After you’ve rinsed your hair, shampoo and condition as normal.