If you'd like natural-looking highlights without the use of bleach, consider using lemon juice to highlight your hair. Pure lemon juice is effective, as well as over-the-counter lemon highlighting sprays, like Sun-In. If you have extremely dark brown or black hair, you may not want to use lemon juice to lighten your hair--it can turn your hair orange or red! But if you have medium brown to blond hair, you'll be able to lighten your hair naturally without consulting a hairdresser. Pregnant women unable to dye their hair during pregnancy can also use lemon juice to lighten their hair.