Using a shampoo and conditioner that are marked as "brightening" or "debrassing" products temporarily removes the brassy hint from hair. These hair products contain a blue or purple dye base that counteracts the hues that are causing the brassy appearance.
To permanently fix a brassy hair shade, a toning color needs to be applied to neutralize the brassiness. The exact shade of the toning color depends on the dominant shade causing the brassy look. Stylists use a shade that is complementary to the color making the hair brassy. For example, blue toning color is complementary to orange and used when the hair has an orange tint to it.
Protecting the hair from the sun, ocean water and pool water helps prevent brassiness from occurring. Shampoos that contain sulfates also cause brassy color.