You get a mix of Xtreme Clean at 1:3 (one part Xtreme Clean to three parts water) and whilst the hot wash is going through the plant simply spray the clusters and the line. It doesn’t have to be a heavy spray, just a good couple of squirts on each cluster with a trigger sprayer and some squirts down the milk line.
Then when hosing down the shed just hose the clusters and milk line. They will all sparkle as if you’ve had the rubbers off and scrubbed. It’s that easy. Save yourself hours, try it next time (and if you don’t yet have any Xtreme Clean you can get some here)