If I recall correctly - been a while, there is a thin metal insert the holds the knob to the blade arm of the control. Last ones I pull I used a pair of pliers to hold the blades (one at a time) behind the face plates so if I left a little mark from the pliers it would not show once installed and then I pulled the knobs off with my fingers. If things didn't go as planned I was considering wrapping a fork which had enough space between the tangs to left the arm/blade to pass between without contact. Wrap the end of the fork with a couple of layers of electrical tape then with a razor or razor knife cut a small section of tape out between the metal fork tangs. The holding the controls and placing my fingers behind the fork which was making contact with the back side or edge of the know use that to provide a better grasps and give that a pull. Never got to using that plan but thought I would share as a possibility. Know I've tried loosening up the metal clips inside knobs like this in the past. Could often get a small thin screw driver blade in to work it loose a bit but you run the risk of deforming the knob.
Likely not the only way but what worked for me.
