91% Alcohol does nothing to clean a very dirty looking Cuetec Cynergy ferrule.

I just got this used Cuetec Cynergy shaft, so I do not know it's history, but I am now afraid that the ferrule can't be made White again, without possibly damaging the CF.

I used a microfiber cloth and 91% Isopropyl Alcohol on it, and it did nothing to clean it.

Still looks the same.

Is there anything else that I could try?

By the way, what I am thinking must have happened in the past is that a cue repair person did not clean the ferrule after putting super glue on the ferrule, during a tip install, so basically, chalk dirt ended up getting stained into the ferrule. This is my best guess though. I do not know.

Thanks a lot for any help.