Mike Rocket J. Squirrel Elliott wrote:

Is there some way to mask off areas of something like a door jamb before
applying paint stripper so that only certain areas are stripped? My aim
with a stripper-laden brush is not nearly good enough, and I need to
remove paint from a two-tone door jamb, where one side of the doorway is
getting new paint, while the other wants to have its paint untouched.

I have used aluminum foil to protect other parts when stripping paint.
If you can slide it under the piece you want to strip, it will work. It
might be better, in the long run, to take off the part where the colors
meet, strip and paint it, repaint, replace, and touch up.

You may cause yourself a whole lot more work - and the purchase of
another color of paint - by trying to do it in place. If it is painted
on, use a steel straight edge and sharp knife to cut the paint film so's
you can get it off.