If it is just rinsing, you can even do that with fresh water. But I agree with everyone else, it would be pointless. If you are worried that it carries some pathogen, rinsing would not remove it. By the way chaeto can carry ich. If that is your concern, just quarantine it for 6-8 weeks. I once did it by placing chaeto in a goldfish bowl, hooking up a simple air pump and placing the bowl in front of a window.