I've done a clear rinse before with ADore and I had pretty good results. My natural hair color is often mistaken as jet black, especially after a clear rinse. I processed mine with a heat cap for 15 mins and rinsed then applied a detangling conditioner.... The shine was incredible for the first week, but afterwards the results weren't as noticeable. I am assuming rinses last around 5-6 weeks (despite my bland physical evidence).
Around 4th of July weekend i'll put a ginger or glorious gold rinse in my hair to lighten it up a it and give it a warm brown hue.