Two polymorphs of Mn₂Sb₂O₇ have been reported, in the pyrochlore structure and in a chiral, monoclinic structure. In both cases, magnetization data have shown prominent features attributable to a ferrimagnetic impurity. Accessing the intrinsic physical properties of both materials thus requires first making them phase pure. We describe our efforts to optimize the preparation of both polymorphs and how we concluded this was necessary, in hopes that future work will be aided by detailed knowledge of this process.