IIRC, the top of the hole is only peened over. Sounds like you have years of trash in the click ball hole. You could find something small, a punch, that will fit inside of the hole. Insert it in the hole and then twirl it about enlarging the hole, removing the peened over top portion of the hole. Then the click ball and spring may come out. You may have to still soak it some in a cleaner, degreaser, to free it all up.
There are instructions on here that tell how to replace the click ball and spring. It involves a Bic pen and a spring bar.