I'm not worried about the shaft changing color, just annoying when you're getting to hit the ball and its grainy between your fingers causing it an unsmooth shot
I use Cue Silk. It works well and makes the shaft silky smooth. It cleans up some of the blue but not all of it. That doesn't bother me, though, because I like the look of a used cue, kind of like a guitar that's been toured with for years.
It's probably just glorified car polish, but a little goes a long way with it.
I consider my blue shafts like a bit of a badge of honor. Mine are smooth and I never notice any gritty feeling in my bridge hand. To me there is just something I really like about the bluing of a shaft. I also dont mind getting some dents and dings in the butt of my cue either. My cue is for playing and it definitely shows.