Rust sounds like you used wire wool, as the nickel silver fret dust shouldn’t rust as such, but may go a dull grey (and blow away) If you use wire wool for polishing, then a pass with a strong magnet should pull the steel wool fragments away from the wood, though the fret residue itself is probably non-magnetic. I’ve stopped using wire wool on guitars because of all the fragments it leaves behind, and use either Scotchguard pads or Micromesh instead.

Rubbing the fretboard with Micromesh should clean up any remaining fret particles. Never had an issue with fret dust on a maple board myself.