Gourd shells have both a thin outer skin and a pithy center that should be removed in order to make them suitable for use as a gourd rattle. These instructions explain how this is accomplished.
Step 1: Scrape off the “skin” (outer husk) of a raw gourd or soak it briefly in water and then scrub off the skin.
Step 2: If the bottom of the gourd has not been cut off, do this now and remove the seeds. A coping saw with a fine blade or hacksaw works well for this.
Step 3: Prepare a 30-penny nail by flattening one end, then sharpening it and bending it at a 90 degree angle. A baby spoon with the edges filed sharp also makes a good tool for this. Another alternative is to do the initial cleaning using a small grapefruit spoon with the sides ground down to make it narrower. This way, the spoon will fit through smaller gourd necks, and the rough front edges will make a good first tool to remove the bulk of the pith when you’re first starting to clean out the gourd.
Remove as much pith as absolutely possible. Finish up with a sharpened spoon or the flattened nail to make a smooth inside surface.
Step 4: Drill the top center of the gourd with a 7/32″ (or smaller) bit. Use an awl to make an initial guide impression so that the drilled hole will be perfectly centered. It is better to make a hole a little smaller than the diameter of the stick where the top of the gourd will actually rest. The hole probably will enlarge slightly as you put it on and off the stick while checking for fit. Use a small rattail file to carefully and gradually enlarge the hole through trial and error to its finished size. Never force the gourd, as it probably will crack.