I have found big differences between shafts and how hard the decals are to remove. I tried many things with Beman ICS Bowhunter shafts and it was difficult. Trad Only shafts were easy! Acetone and green scouring pad or paper towel.
On a related note, a friend of mine said that carbon shafts are porous and will absorb solvents. He said this caused some fletching adhesive failure I had on a camping trip...
So far I have not noticed any damage from the acetone to the strength of my shafts. If it doesn't hurt the woodgrain finish I doubt it could hurt the carbon.