This is my way,fast,easy, and safe! I bought a commerial grade pvc pipe cutter made by rigid ,any model will work. Center ball in cutter make sure you leave golf ball title on one half,sqeeze cutter and cut ball in half,it will cut perfectly and their will be a few index marks to alighn ball halves up ,put a few drops of supper glue on each half and press together ,cant see seam,if you do a light sanding will make seam dissapear. I forgot to add,,agter cutting remove outer shell ,simply by prying light with small screw driver.
