Keycap cannot be removed from metal part..
and metal part is hard to remove from keyboard.
You can, but you don't necessarily need to.
Having got the key off that far, you can lubricate the stabiliser then put the key back.
However if you do want to remove that key, get a flat-bladed screwdriver. Put it underneath the key, against the stabiliser (if you're right-handed, the right side). Push the screwdriver gently to the right, while you pull the keycap gently to the left. The top of the stabiliser will unhook from the white plastic clip and you can remove the keycap. Remember it shouldn't require much force, and that you're trying to
stretch the stabiliser ever so slightly, not
bend it.