Try something gentle first like white spirit, paraffin or petrol.
It may take a fair bit of rubbing with a cloth but shoukd come off. Ive used white spirit on many bike oarts, for degreasing and its never damaged any anodised components.
If impatient, try a paint stripper eg nitromors, it is not as pitent as it used to be but test a snall aee first, be careful whrn using ad it will burn skin if slpashed.