soaking it day(s) with PBW works great and I assume oxiclean will as well. Rinsing and flushing is bit of a pain. Faucet, tube cleaner and rag on wire are great ideas. But I find that if I've soaked it well and transfer it while still wet (!do *NOT* let it dry dirty!) to clean water I can usually coil and manipulate water through it and let the water drain out to such a degree that it is clean enough. And I always soak it in sanitizer right before using.
You've got to *really* let it soak though. And with a powerful cleaner.