In the manual is so that you get the best milk foam when initially foams cold and then hot. I think this is unnecessary, I foams now in principle immediately fired up and had to almost 1 minutes into absolutely perfect milk foam. My wife is about as excited as I am.
Then simply swing short and everything is clean again, really a great solution with the magnetic stirrer. Of course you can do everything in the dishwasher.
I'm using 1.5% H-milk in the fridge cold and that really makes perfect foam.