So you can’t afford that color job for at least a couple more weeks. Vinegar will be more than happy to fill in! Since some minerals in water create a brass look for un-natural blondes and redheads, vinegar helps bind the color to your hair for a longer time. Take 1/2 cup of distilled vinegar and 1/2 cup of filtered water and apply to hair. After, rinse with cool water. The cool water is gentle on your hair and opens up the follicles. This remedy will also have your color shining brighter than before.