Use the 30ml. a 10ml. piston and a short piece of tubing
Connect the tubing to the 30ml. piston and fill it half full of water
Turn the 30 ml. piston upside-down and gently press the plunger to remove the air bubbles
Push the plunger of the 10ml. piston in and then connect to the tubing
Pull the plunger of the 10ml. piston out and in and explore the system