I wrote and have used much a Visual C++ program which can edit .OBJ files including renaming materials.

The problem arises when someone (me or someone else) renames a material in the .OBJ file. An example was with the Businessman in the early history of Poser; someone editing his .OBJ file mistyped "jacket" as "jaket", and Poser (3?) thereby set up a material description (DeathMetalDesk's "phantom debris loaded from the .cr2" for "jaket" in his .CR2 file. Then someone else corrected the typo in the Businessman's .OBJ file, and Poser reading this set up a new material description "jacket"; but the material description "jaket" remained as junk. A way is needed to check all geometry files and embedded geometries (including of all alternate geometries) and so find all unused Poser material-descriptions, and optionally remove them.

That will have to be done within Poser (or in Poser Python, if Poser Python can remove Poser materials descriptions), unless Phil's PZ3 Editer can read and decode .OBZ files.