  The suppression of spurious events in the region of interest for neutrinoless
double beta decay will play a major role in next generation experiments. The
background of detectors based on the technology of cryogenic calorimeters is
expected to be dominated by {\alpha} particles, that could be disentangled from
double beta decay signals by exploiting the difference in the emission of the
scintillation light. CUPID-0, an array of enriched Zn$^{82}$Se scintillating
calorimeters, is the first large mass demonstrator of this technology. The
detector started data-taking in 2017 at the Laboratori Nazionali del Gran Sasso
with the aim of proving that dual read-out of light and heat allows for an
efficient suppression of the {\alpha} background. In this paper we describe the
software tools we developed for the analysis of scintillating calorimeters and
we demonstrate that this technology allows to reach an unprecedented background
for cryogenic calorimeters.
