I will present a new leptogenesis mechanism based on the
standard type-I seesaw model that successfully operates at
right-handed-neutrino masses as low as a few 100 TeV. This mechanism,
which we dub wash-in leptogenesis, does not require any $CP$ violation
in the neutrino sector and can be implemented even in the regime of
strong washout. The key idea behind wash-in leptogenesis is to
generalize standard freeze-out leptogenesis to a nonminimal cosmological
background in which the chemical potentials of all particles not in
chemical equilibrium at the temperature of leptogenesis are allowed to
take arbitrary values. This sets the stage for building a plethora of
new baryogenesis models where chemical potentials generated at high
temperatures are reprocessed to generate a nonvanishing B-L asymmetry at
low temperatures. As concrete examples, I discuss wash-in leptogenesis
after axion inflation and in the context of grand unification. I
moreover discuss the connection to spontaneous baryogenesis driven by an
axion-like particle with generic couplings.