What is it: Tinted Hair Colour Treatment. Best for: Coloured or non-coloured hair. O&M CLEAN.tone helps to keep your hair colour looking fresh, nourished and shiny like you have just visited your colourist. COOL BLONDE Recommended to help maintain cool ash tones on blonde to very light blonde hair. Helps eliminate unwanted yellow or brassy tones. Ideal for hair colour levels 7-9. Can be used on lightened and natural white/grey hair.