Thankfully, I have very dark brown hair and there is no need to mix colors. If I did that, I'd probably wind up with green hair.
You all are mentioning "ash"; ash is notorious for adding in red. I learned this the hard way, I purchased light ash brown on year and come out with Strawberry Blonde Hair (with nice dark brown eyebrows) yeah, that was attractive.
I'm planning on coloring my few grays that have appeared on my hairline, which like most of you is only visible when I pull my hair back (which is something I do daily). I do have 1 box of Herbashine in stock and a bunch of other ones of permanent color, which I may try to take back to exchange for a non permanent color.
I also thought about going to Sally, but I'm confused as what to buy. How do I choose the white stuff (sorry, I don't know what the technical term is)?