The best way to describe a composite anything is a whole lot of fibres that are encapsulated by a bonding agent. The wetting out only refers to the amount of the fibres that are fully encapsulated by the resin. This is actually really important. If the resin amount is insufficient then there will be fibres that have no resin all around them. That will mean that these individual fibres can then detach from the structure. As the fibres themselves are generally in the 4um to 1um, so like 2/10ths of a thou to 4/10ths of a thou is diameter. These are very small, and if you get one in your hand, you are unlikely to see it. All that said, I have never had any issues with any carbon fibre parts and cue shafts I have made. The exposed section of a fibre that is encapsulated by resin seems to be just fine even though your hand etc is rubbing against it. It can be sealed by things like car paint clear coat, or CA , or any finishing resin that is compatible with the substrate resin. I don't recommend sanding a carbon shaft for it's cleaning at all. When you 1st get it, and it seems to be sticky to your skin, some light grey scotchbrite draw polish will work well. Once you start to see black coming off the cue shaft, that is resin and carbon fibre coming off. Becue use of black polish, I assume is like shoe polish, is probably a good idea. It will leave behind a very thin smooth finish on the cue shaft. IPA will not harm any epoxy resin that I know of. However, things like Methanol, denatured alcohol, Acetone, nail polish remover, super glue remover, MEK, are all solvents for epoxy resins. Baby wipes and lens cloth wipes are fine, to use.
The best thing with carbon cue shafts, is keeping chalk off your hands, or glove and off the shaft itself. Cue chalk is actually very abrasive .
Neil