I scored a nice block of very curly hard maple recently. Figured it was a good time to try to stain it with a method I've heard about but never tried. I put steel wool in a piece of my wife's tupperware and filled it with white vinegar. A week later it looks like the inside of a porta-John if you get my drift. Turned the call and sanded to 320. Wiped it on the call, briefly hit it with the torch to "activate" it as I've read about, and viola! It really makes the figure pop! The stain raised the grain so I sanded with 320 again and then on up past 800 and then finished it.
The toneboard is Delrin on this one.
I put an unfinished block of the same piece of maple in the pic for comparison.