  We predict the non-linear non-equilibrium response of a "magnetolyte", the
Coulomb fluid of magnetic monopoles in spin ice. This involves an increase of
the monopole density due to the second Wien effect---a universal and robust
enhancement for Coulomb systems in an external field---which in turn speeds up
the magnetization dynamics, manifest in a non-linear susceptibility. Along the
way, we gain new insights into the AC version of the classic Wien effect. One
striking discovery is that of a frequency window where the Wien effect for
magnetolyte and electrolyte are indistinguishable, with the former exhibiting
perfect symmetry between the charges. In addition, we find a new low-frequency
regime where the growing magnetization counteracts the Wien effect. We discuss
for what parameters best to observe the AC Wien effect in Dy$_2$Ti$_2$O$_7$.
