I've cut them out of a couple of my tops by carefully trimming close to the stitching along the neck and armholes. It seems to work well, doesn't roll up or show. This is strictly a no-sew alteration on my part.
I have one top that that I haven't attempted because I think I'd need to sew some of the raw edges. I can't sew technical fabrics to save my life. Well, I can, but it looks like rubbish when I'm done. Of course that is my favorite top, and also has the worst of the shelf bras