To get decals off
Same as a steel/ally frame?
use a hair dryer and isopropyl alcohol. id stay away from acetone.
Hydrocarbon ones like white spirit are mild on carbon IME - gone to town on carbon rims with white spirit before to get rid of tub glue.
Another one to avoid would be methylene chloride which is commonly found in paint stripper - quite a potent solvent that might start to penetrate the resin.
Any solvent (within reason) should be fine, you can't dissolve epoxy once it's cured, IPA, meths, white spirit, acetone should be fine.
Any paint, clear coat or varnish is a different matter, so test it somewhere inconspicuous first.
I'd not combine a hairdryer and solvents. Either let the solvent dissolve the glue, or warm the glue up so it melts, hairdryering it will just evaporate the solvent!
If using a hairdryer, don't let it get too warm, if it get's warmer than the material was originally cured at then it can cause issues.
Zipp recommend using acetone on their wheels for cleaning glue off.
We use surgical spirits to remove it. Unless its the small stickers that the French supply for their Enduro races and then it's a credit card, a lot of patience and two hours to spare.