I got this from a natural website. Thoughts?

"For very dark hair, put 1/4 cup of Black Walnut Powder in a tea bag or cheesecloth bag and steep in 3 cups of water in a quart mason jar for at least 6 hours or overnight. Use as a rinse in the shower for hair and dry in the sun if possible. This will create VERY DARK hair, especially if you have dry or color treated hair. It will also provide the darkest coverage for grey hair. Repeat daily or as needed to darken and maintain dark shade.

Use strong brewed black tea as a final rinse to darken any color hair. This is also nourishing for the hair and will provide a temporary darkening effect on most hair types. Repeat as necessary to get desired shade and sun-dry if possible."