First, you don’t have to consolidate to export an OMF file. If you choose “Avid 3D audio” in the export settings, you can easily export OMF1, OMF2, or any number of file formats.
Second, you refer to consolidating projects. Actually, you consolidate clips or sequences. Consolidating will merely copy all media used by the clip or sequence you choose. A typical way to consolidate is to hi-light a sequence and allow the consolidation command to duplicate it and relink the new media to it. You will have to use another tool (or two :->) to delete the unused media. Research using the “select unreferenced clips” command located in the bin’s hamburger menu. There are also third-party softwares that can be used to locate clips used in a project.