  We present a detailed analysis of the spectral data of Borexino Phase II,
with the aim of exploiting its full potential to constrain scenarios beyond the
Standard Model. In particular, we quantify the constraints imposed on neutrino
magnetic moments, neutrino non-standard interactions, and several simplified
models with light scalar, pseudoscalar or vector mediators. Our analysis shows
perfect agreement with those performed by the collaboration on neutrino
magnetic moments and neutrino non-standard interactions in the same restricted
cases and expands beyond those, stressing the interplay between flavour
oscillations and flavour non-diagonal interaction effects for the correct
evaluation of the event rates. For simplified models with light mediators we
show the power of the spectral data to obtain robust limits beyond those
previously estimated in the literature.
