How to Use a Shampoo Color Cap. Coloring your hair is great for uplifting your mood, but getting it right and maintaining it is a hassle. The key to maintaining your look is keeping your roots gorgeous, and that is also the most difficult part. Touching up roots is easy when you use this color cap technique to ensure your ends come out perfectly too.
Mix your leftover color with about 1 tbsp. of color-safe shampoo in a mixing bowl with the applicator brush.
Apply the mixture to your ends with the applicator brush, and massage it into your hair down to the roots just like when you normally shampoo your hair.
Allow the color to set for 5 to 10 minutes. Make sure you let the treated shampoo sit in your hair for long enough to finish the setting process.
Rinse your hair and shampoo it with untreated color-safe shampoo. Then condition and style it like you normally do.