I always "rinsed" my coffee maker with plain water after brewing a cappuccino or hot chocolate... until I discovered Keurig's "Rinse Pods".  They do a much better job of  cleaning the residue out of the "lines" than simply plain water!  I  brew so much cappuccino, hot chocolate and the like for my family that I use a "Rinse Pod" twice a week instead of just once to keep the coffee maker fresh!