I really struggle with this. This week I have been using PhilC's Poser Tool Box which can create a full list of morphs for a figure then delete all the morphs on the list.  I go through the list and remove my character, the expression morphs and the JCM morphs before running the delete script. svdl SpawnCharacter is great for V3 but I am using this Poser Tool Box method as my latest way of dealing with Ruduced Resolution and third Party figures as well as M2 and V2. Hmm. Not perfect but it seems to be working.