Filtering surface from a solid

Morning all,
i have a model element (roof) that as point editing. I want to get all the “top surface”. Basically not the side or underneath.
I looked at the Surface.FilterByOrientation. It finds the verticals but i can’t seem to find a way to remove them from the original list. I need to find a piece of information but there’s no “ID”.
Any help is much appreciated

I managed to clean it up using this, im still open to smarter way to do it :wink: