Easy, fast, worked better than I’d expected.
I read the directions, did a bit of researched, applied as directed, wrapped my head in plastic and sat in the sunshine for 40 minutes.  The deep black permanent dye is gone, leaving me with soft, natural hair.  The ONE drawback is the smell, but it’s not that bad.  I used clarifying shampoo, then rinsed my hair in warm water and baking soda.  Then rinsed it in white vinegar and warm water.  Shampoo’d and conditioned again; while wet I could smell a little bit of sulphuric aroma,  but when dry the smell was almost gone.  The next day I washed and conditioned again and when it dried the smell was completely gone.
Rating: 5 stars