Window whiskers removale

[western star]

I have played around with some old doors trying to find the right way for removing the window whiskers and all I do is bent them or screw them badly. I can see the way they lock in but when I go to take them out they seem to have a mind all their own. I am changing doors and the ones that are in my existing doors are only a couple of year old so I want to save and use them. What is the trick please.