I went out this morning to look at a roof of a local Pizza Hut. I was told it was just painted a year ago and it's already got black stuff all over it. I'm wondering if it's a combination of algae and grease. When you rub in it, it kind of balls up. Has anyone had any experience with this? I'm not even sure I have the equipment to do it, but in my mind, it would take some strong SH mix with Roof Snot for dwell time. I don't have an actual soft wash set up, but I think a simple unit could be set up relatively easily. I did come across some info that you could use one of the electric sprayer set ups you get from a farm supply store, but I don't know how effective that would be. I have read that it's a good idea to rinse metal roofs. I certainly don't want to take the paint off, and I can see in some areas that it's already peeling. I wonder if it was a shotty paint job to begin with. The manager said he could take a rag and with some water, just wipe it clean, but I don't think that's a good plan for the whole roof! I also wonder the feasibility of just using some pressure and water to get it done that way. Any advice/input would be greatly appreciated.