I bought a black/silver Slingshot several weeks ago and experimented with the cover a little bit.  I added some surface, then decided to add a little bit of polish.  I had some Neo Tac Renew-It left over and it seemed to always apply well by hand on a couple of my other balls.  After I applied some to the Slingshot, it looked like the white lettering turned a little yellow.  I thought it might just be the lighting in my apartment.  Pulled the ball out for league last night and the lettering was really yellow, pretty much the exact color of the polish.  I have used the exact same polish on other balls with white lettering without any change.  I know it should not affect performance at all, just wondering if anyone has experienced anything similar?