I have read some of the respones re Loreal Color Zap for removal of hair color. Will this product remove the product "Shades?" I am approx 75% gray and would like to simply go all gray. My 1/2" roots are natural gray and I have about 1 1/2" of "Shades" with the ends (about 1") being permanent color in a medium brown with reddish tones. If Color Zap takes out the dye, do I HAVE to re-color or will my gray return where the color was? Thanks for any info.