Out of sight, out of mind. That's your steam wand's inner walls. Sure, you purge after steaming milk, but did you know that mineral deposits on the inner walls can prevent a complete purge? As the machine cools down, a partial vacuum is formed in the system which can result in the residual milk residue getting sucked up towards and eventually into the boiler. Yuck!
The Steamy Wanda is designed to get in there to clean out that gunk and get you back to steaming perfectly textured milk. It's also great for cleaning portafilter spouts and other nooks and crannies!