RE: Removing spray paint...
Acetone is a solvent. Solvents dissolve glues. A carbon shaft uses glue to bond the carbon layers.
I know of only one arrow maker that reccomends acetone and that is Carbon Tech. The others mention nothing about acetone and some, Carbon Express being one of them, reccomend against it.
Using acetone once or twice will probably do nothing or little to weaken the shaft but used regularly it will very likley begin to break down the glues that hold the carbon layers together.
Scrape off the paint with a dull knife. It will flake off. Then you can retape, repaint, let dry and refletch.
Wraps are soooooooooooooooo much easier but to each their own.