Can We Harness Black Holes for Faster Flybys?

[Dr Wu]

With regards to the Blandford-Znajek process (about which I've only recently become aware), would be possible, at least in theory, to tap into the rotational energy of a charged black hole, this by using its revolving field-lines as a kind of 'magnetic assist' to increase the acceleration of, say, an unmanned probe making a close flyby? Or is this completely potty?

 

[ViperSRT3g]

I would like to know if the physics behind this would vary with object mass. I think smaller particles would be greatly affected by this more than larger objects (Because black hole).

 

[Dr Wu]

Moreover, it would be interesting to know if the above also applies to other celestial bodies with a high magnetic flux - neutron stars and magnetars especially.