OK. Let's take V4 for example. The arm textures cover several different material groups. But just for grins let's say you add the vascularity to just Skin Arm and Skin Forearm.

The problem with deleting is, you have to select one material group at a time and delete the layer you want to remove before you change it to something else. In that case, a script wouldn't exactly be NECESSARY, as you can do it with a bunch of clicks. But a script might make things faster.

Of course, the other alternative to remove all those vascularity layers is to reapply the base material that you started with. That would remove ALL of the layers that have been applied to the character.