Thanks Danny.
The vinegar and steel wool stain I learned from aaron, a member here on PA. I use household white vinegar, but I imagine any vinegar or maybe even any acid will work. Might be worth experimenting. I keep a big glass jar full of the vinegar and I regularly add old bits of steel wool pads that are not practically useable anymore. it seems to take several weeks of aging before it really affects the wood.
I use a paper towel or scrap of cotton t-shirt. I apply it before finish sanding. Used between each successive grit of paper, it functions to stain and raise the grain between sanding. It also makes it easier to to track your sanding coverage and highlight any tool marks. apply one last time after your last sanding coat and first finish coat.
One issue I ran into on this bow was that I got a little sloppy with applying the first couple coats of shellac, which required sanding some runs out with some 220 grit. The issue was when this exposed patches of bright osage where sanding out the runs. Reapplying vinegar/steel wool to these areas worked well enough.
I like the aged look and the grain standout, but it does have greenish hue that makes it look sickly to me. It looks more like authentically aged osage after some time in the sun. I am not to fond of the look of this stain on yew, but it looks great on ash, and vine maple.
aaron recently posted a vine maple bow that he used this vinegar/steel wool applied after applying a tannin rich solution to the wood surface it significantly darkened the effect.