[jasa]

Hi G
These can be a right pain, mine proved impossible to just press in due to corrosion (although only a small amount)

In the end I adapted a pair of pliers by grinding the teeth from the hollowed out jaws, drilling a small hole and inserting a suitably sized shank from a drill slightly smaller than the sprung loaded pin, secured by a touch of weld on the outside - Imagine a circle with a line marking the radius and I think you'll get the idea. The pin only needs to protrude into the jaws by about an 3/16" or so.
I also glued a small piece of felt to the jaw opposite the pin, in order to give the knob some protection.

I also filed down a soldering iron bit so I could apply a small amount of heat direct to the pin. The WD40 can also help of course but wasn't enough in my case.

You need to be careful not to apply too much force as you can get a lot of leverage from the pliers, and not too much heat because the knobs can be a bit delicate but having spent a long time fruitlessly trying to remove said knobs I found most of them came out easily with this mo. Two were slightly more reluctant but with patience all was well. If at first you don't succeed...
When I got them off, I could see why they didn't want to move.

Good luck

Mike