Spilled brake fluid?
The original is not that easy to remove, and part of my paint lifted on removal. But there was paint work that needed to be done, so not such a big deal.
I don't know why the paint need be completely stripped. Paint is not supposed to be brake fluid proof. I also don't know why you would blend into the doors.I would see how well the paint matches before painting things that don't need painting
I would consider doing all the film that needs doing, whatever you do.