DIY Hair Toner This is magic for any blonde trying to keep the yellow/brassy tone out of their tresses. I used Suave deep conditioner with one drop each of Splot purple and blue hair color (found at Target). I left it on after shampooing for 3 minutes. There was a slight blue tinge to some particularly light highlights, but one wash sorted them. The results: softer contrast, beautifully cool tone, great hair condition. Use once a week or as often as needed to keep brassiness at bay.