Or letting the TFR/Muckoff etc dry out before rinsing it off. They could also get water marks from the mineral deposits in the water they used to clean it, typically it's more likely to happen in both cases if they try and clean the bike with the engine still hot/warm. DAMHIK. It's then a bu88er to get offThe staining could be down to the dealer using TFR and not diluting it correctly.