Based on a whole bunch of first hand experience:
(1) Like was said, you're not starting a fire, you are just charring the surface.
(2) Keep a spray bottle of water to tame what you don't like.
(3) Rather than sand, start off with a wire brush. I prefer a small brass one, because it's not as aggressive as a wire brush we'd use out in the machine shop.
(4) After brushing, then I'd touch up with sanding. Start with just a piece of paper in your hand, because a sander works fast and you can better control when you want to stop with just a piece of sandpaper.
(5) If you want the dark splotchy, a little black, water based dye would get you there. Less would, probably, be better, because, like water color on paper, results happen quick and, with the penetration of a dye, there isn't much in the way of going back to go (though a bleach might get you there).
That dye can, also, lend itself to the distress effect. For example, a toothpick touched in the dye, then touched to the surface may get you where you want to be.
(6) Don't forget, the wood you use has two sides, so you can experieent.