cleaning up a recovered project?

RH7, .chm help.

Our help projects at some point were lost/corrupted/whatever, and a tech writer prior to me recovered them by reverse engineering the chm files. My understanding is that this results in a lot of extraneous files and folders, as well as folder structures, within the projects that aren't needed (or necessarily right, given the nature of extracting a project out of a finished chm file).

I would like to clean these up. Are there any guidelines anywhere regarding what file types are safe to expunge, or what the most convenient method is? I'm half-way tempted to start a new project for each existing project and simply import the .htm files and .css file from old to new...