A new heat treatment for Internal-Tin Nb3Sn strands is described. The heat treatment uses Nausite membranes to decrease the volume fraction of the η phase and therefore minimize its liquefaction—ultimately resulting in better connected Nb3Sn. The heat treatment requires only one stage aside from the final Nb3Sn reaction stage. This heat treatment enables an increase in critical current density (at 16 T) of 28%.