Almost any stellar population present in a galaxy should contain
 a number of asymptotic giant branch (AGB) stars. This phase of
 stellar evolution is very difficult to model, and hence the
 inverse issue of trying to model the output of a composite stellar
 population as a function of time is extremely uncertain. We
 propose a search for emission from the circumstellar shells
 around the AGB stars present in the nuclei of M31 and M32,
 nearby, quiescent galaxies with old stellar populations.
 This emission will be characterized by the presence of a silicate
 feature at 10 microns.