Cas Cas shakers have many names. Use them as a regular shaker or swing them around to make rhythms.
I did use supports but only to the bed to keep the inside of the shaker clear. More infill may be a good idea; this was my first print so I used as little as I could in case it didn't work. For the plugs I needed to use a raft but no supports.
After removing the raft and support put what ever you want to make shake in the shaker in the shaker. This can range from a great many things: sand, pebbles, beads, rocks, anything that will make sound hitting the sides that you might like. If you don't like the sound of what you pick, try something else before finishing; just plug the hole with a finger or thumb and shake to test. Experiment with different amounts of what ever you choose for different pitches. If you just want a regular shaker then plug it up with the plug, some glue on the inside of the hole and the plug (I used E6000), hammer it in, wait for it to dry, and then saw off the extra plug sticking out. Cork and wood are suitable substitutes for the printable plug.
When you find the pitch and material you like cut a short length of string or rope. Different shakers have different lengths; make sure you can hold one end of the rope in the top half of your hand and loosely wrap around your hand. Leave space to put the ends in the shakers.
Place the end of the rope into the cas cas, put some glue (I used E6000) around the inside of the hole and the plug, hammer in the plug keeping the rope in the holes, and wait for the glue to dry. Once dry saw off the end of the plugs as flush as possible without cutting off the rope. Cork and wood could also work as plugs.
The cas cas are ready to play!
Printed Cas Cas Demo
Some one FAR better than I...