Performed slowly and smoothly this is a nice effect. The half dollar is solid and shown at the fingertips. As described, the coin is hidden as the hands are closed and then opened to show that it has changed to a Chinese coin with a hole all the way through it. You can see right through the hole to the palm of your hand.

As one drops the Chinese coin into the other hand to pass it out for examination, the description is correct. The magician will either have to use a classic palm or finger palm, and then be able to ditch the part that you want to keep secret.

If done properly, the surprise at the coin with a hole in it should provide ample opportunity to do the "stuff" without getting caught.