color lifting, foiling, stuff like that

I've currently got a dyed black hair color. Revlon Colorsilk-- a fairly gentle permanent dye, as far as box dye goes. I've been considering changing it up a bit. I'd like to go dark brown. Or maybe put a streak of some crazy color in with my black right now.

So if I decide to go dark brown: Will a dark brown box dye be able to get enough black out to tone it with a warmer brown shade, and will it (possibly) turn out alright? I know that nobody can answer this for sure, because there are so many possible variables. I know that it's pretty much impossible to go from black to, say, blonde without some serious color lifting, bleaching, toning... stuff like that. But all I need to do is get a little bit of the darkness out and tone it brownish. I wouldn't need to do a lot of color lifting, so I'm wondering if I need to mess with the color remover at all.

If I decide to stick black and put some crazy color in it: I'm wondering how I should go about it, and how I should maintain it. Would it be better to bleach a streak of hair, or to try using a lifter on it? I'd be removing the black color, and then using semipermanents/stains in colors like pink, blue, purple, whatever-- but how would I best achieve light enough hair to do this? And second: As far as maintaining the black + crazy color thing, I'd need to keep dyeing my hair black, but keep myself from dyeing over the bright colors. I thought I'd achieve this by wrapping my colored streak in foil before using the black dye, but on the box it says to not use any metal during the dyeing process-- metal combs, metal clips, those are all out. What exactly does metal do? Is this a good idea? Will it somehow react with the dye, or damage my hair?

Thanks so much for reading and replying; I know this is a lengthy question.

Why don't you get some synthetic extension streaks in your hair to try out some outrageous colors? If you don't like it, take it out, with minimal damage to your hair.