  WIMP-type dark matter may have additional interactions that break baryon
number, leading to induced nucleon decays which are subject to direct
experimental constraints from proton decay experiments. In this work, we
analyze a possibility of continuous baryon destruction, deriving strong limits
from the dark matter accumulating inside old neutron stars, as such a process
leads to excess heat generation. We construct the simplest particle dark matter
model that breaks baryon and lepton numbers separately but conserves $B-L$.
Virtual exchange by DM particles in this model results in di-nucleon decay via
$nn\to n\bar\nu$ and $np\to ne^+$ processes.
