Tone down brassy highlights with a professional toner, a purple toning shampoo or with lowlights. A good shower filter may also be helpful because it filters out the iron deposits in water, preventing them from attaching to the hair.
A toner works to counteract the brassy hair color by toning down the hair shade. Purple toning shampoo balances out yellow and orange tones because purple is on the opposite end of the color spectrum. Lowlights add a darker variation to a person's hair color. A stylist applies lowlights strategically to cover areas of the hair that are too bright or light.