  The collisional Penrose process received much attention when Banados, Silk
and West (BSW) pointed out the possibility of test-particle collisions with
arbitrarily high center-of-mass energy in the vicinity of the horizon of an
extremally rotating black hole. However, the energy that can be extracted from
the black hole in this promising, if simplified, scenario, called the BSW
effect, turned out to be subject to unconditional upper bounds. And although
such bounds were not found for the electrostatic variant of the process, this
version is also astrophysically unfeasible, since it requires a maximally
charged black hole. In order to deal with these deficiencies, we revisit the
unified version of the BSW effect concerning collisions of charged particles in
the equatorial plane of a rotating electrovacuum black hole spacetime.
Performing a general analysis of energy extraction through this process, we
explain in detail how the seemingly incompatible limiting cases arise.
Furthermore, we demonstrate that the unconditional upper bounds on the
extracted energy are absent for arbitrarily small values of the black hole
electric charge. Therefore, our setup represents an intriguing simplified model
for possible highly energetic processes happening around astrophysical black
holes, which may spin fast but can have only a tiny electric charge induced via
interaction with an external magnetic field.
