I can't think of any quick way of doing that. There are products that will allow you to figure out file dependencies, .cr2 files are basically scripts that load other files, and have the full relative paths of those other files in them. Opening them and checking them manually would be a major pain. I would pick up a program that would help you get a listing and run your purge from that output. You are specifying Poser content on a DAZ forum so I assume you are not using Poser. In any case, Check out Dimsension3D store, it has a lot of utilities that might be useful for that.