Pat how did your S24 go with steaming? What tip did you use? Thanks I am still hoping for a happy ending, I am a sucker for them. I am 99% sure the problem is dirty old milk somewhere, being in a rental the machine was very much unloved. I had to back flush the holy snappin duckshit out of it just to get the shots to stop tasting bad, so surely the milk trail would be even worse! Most likely it sucked some milk back up into the boiler, I am soaking the boiler now in descale after getting permission from Lacehim haha