Summarize this article:

Mix 1 cup of water with approximately 2 tablespoons of freshly squeezed lemon juice in a medium-sized bowl. Pour the water and lemon juice into a spray bottle. Use clips to section your hair up, and thoroughly spray each section of your hair. After your entire head of hair is sprayed with lemon juice, run a wide-tooth comb through your hair. You could also spray smaller sections of your hair for highlights. Simply section off the pieces of hair you want lighter, put a towel underneath that section of hair, and spray that individual portion of your hair. Go outside and let your hair be exposed to the sun. The sun will react with the lemon juice to lighten your hair. The sun will dry your damp hair. Be very careful to wear a protective sunscreen while outside. After your hair is fully dried, rinse out the lemon juice from your hair. You can shampoo your hair normally, but make sure you condition your hair. The lemon juice is notably drying to your hair.
Mix together water and lemon juice. Apply the mixture to your hair. Expose your hair to sunlight. Rinse your hair.