  Recent investigations have shown that Fe$_{1+y}$Te$_{1-x}$Se$_{x}$ can be
made superconducting by annealing it in Se and O vapors. The current lore is
that these chalcogen vapors induce superconductivity by removing the magnetic
excess Fe atoms. To investigate this phenomenon we performed a combination of
magnetic susceptibility, specific heat and transport measurements together with
scanning tunneling microscopy and spectroscopy and density functional theory
calculations on Fe$_{1+y}$Te$_{1-x}$Se$_{x}$ treated with Te vapor. We conclude
that the main role of the Te vapor is to quench the magnetic moments of the
excess Fe atoms by forming FeTe$_{m}$ (m $\geq$ 1) complexes. We show that the
remaining FeTe$_{m}$ complexes are still damaging to the superconductivity and
therefore that their removal potentially could further improve superconductive
properties in these compounds.
