Any 3D modeling program can remove or add.and nope there isnt a way to make something non editable for a good or any 3D modeling program.
in carrara 7 Pro all you have to do is go into the model tab,which is the little wrench looking thing on the upper right hand corner (..dont know if its same in the 5 or 6 version.)
Make sure edit mode is set to modeling mode,(the 3 choices in that section are modeling mode,animation mode,uv editing mode)
in the selection mode select either regular selector or the vertex selector depending on how you wanna delete (remove)(then of coarse select the points,vertices,poly's ect..) then just press delete on your keyboard.
Had to edit this. left the last part bout selecting the vertices ,polys,ect out.
I forget sometimes that most just use 3D modeling Programs just to render their Daz/Poser content, and might not know what the crap I'm talking about.
If you need any help let me know,I'm modeling something everyday so im sorta sure i bumped into most of those annoying little 3D problems .
goodluck