I have been looking around for a way to swap out the knees on my Cannonball ever since Fun Pub and Hasbro told us we are SOL. I have found may ways of removing pins and have done all before. I am even making a modified watch wristband pin press that will be adjustable. The two suggested methods are the light hammer and pin press method, and the hot pin/rivet method. Neither work without damaging your Cannonball figure. The knee is made of a much harder gold plastic with a higher melting point than the softer black plastic of his calves. If you try tapping it out, you will break off the thin black plastic on the outsides. If you try heating the rivet you will greatly deform the black plastic long before the gold plastic releases the pin. Also the knee rivet is apparently not your run of the mill type. I learned the hard way and now have to get a new Cannonball to keep the value of my box set. If anyone out there HAS had luck swapping out their knees, please post a detailed how.