  Using a recently developed technique to estimate the equilibrium free energy
of glassy materials, we explore if equilibrium simulation methods can be used
to estimate the solubility of amorphous solids. As an illustration, we compute
the chemical potentials of the constituent particles of a two-component
Kob-Andersen model glass former. To compute the chemical potential for
different components, we combine the calculation of the overall free energy of
the glass with a calculation of the chemical potential difference of the two
components. We find that the standard method to compute chemical potential
differences by thermodynamic integration yields not only a wide scatter in the
chemical potential values but, more seriously, the average of the thermodynamic
integration results is well above the extrapolated value for the supercooled
liquid. However, we find that if we compute the difference of the chemical
potential of the components with the the non-equilibrium free energy expression
proposed by Jarzynski, we obtain a good match with the extrapolated value of
the supercooled liquid. The extension of the Jarzynski method that we propose
opens a potentially powerful route to compute free-energy related equilibrium
properties of glasses. We find that the solubility estimate of amorphous
materials obtained from direct coexistence simulations is only in fair
agreement with the solubility prediction based on the chemical potential
calculations of a hypothetical "well-equilibrated glass". In direct coexistence
simulations, we find that, in qualitative agreement with experiments, the
amorphous solubility decreases with time and attains a low solubility value.
