I have found in the bows I have refinished that the stress cracks are mostly in the existing finish. So I carefull remove it, especially over any lettering. I use 00 fine steelwool and wet sand in the sink, Start with 320 or 400, then to 600 or 700, then to 1000 and on to 1500. Always sand lightly and if you cant decide how course use the lighter grit. Stop often and inspect what u have done. Wet sanding with give you a better visual aid in inspection also. But in no way em I telling you what to do to your bow. This is only how I do mine. Good luck, use patience and enjoy what you achieve.
Danny J