Massage 2 tablespoons of lemon into your scalp. Leave it in your scalp for about 2 mins. I know this will sting. Then mix 1 teaspoon of lemon with 1 cup of water and rinse your hair with it.Repeat daily until no longer needed.You can also squeeze an entire lemon into a bowl and mix with 5-10 tablespoons of coconut oil.Massage the mixture into your scalp and leave it in for 20-30mins and rinse with a mild shampoo.assage 2 tablespoons of lemon into your scalp. Leave it in your scalp for about 2 mins. I know this will sting. Then mix 1 teaspoon of lemon with 1 cup of water and rinse your hair with it.