I believe the tools you're thinking of are MAT pose files. My understanding is; They work by clearing away any textures and setting materials to white. They have to be made for each specific group of characters individually due to different grouping in each type. As static un posable meshes, props, unless parented to a character, won't accept MAT poses, and any MAT pose would have to have all the materials and groupings of the specific mesh in any event. Simplest way would be to take an all-white image and apply it as a texture to replace any existing texture, then make sure the material colors don't include any colors. It may be possible to do a python script to do this in ProPak or P5, but I don't know of one. You might try doing a search on python in the freestuff in case one already exists.