Has anyone ever experienced staining on aluminum siding? I have owned my house for 3 years--it was built in 1977. This happens every winter, it starts off slowly, but brownish black dripping stains appear every winter and it's driving me crazy! They wash off in the spring with the rain, but I don't know what to do. I have had the home inspector come back and he can't figure it out. It only happens on one side of the house, although there is some clear vapor/water on other sides of the house--the back side is the only side where it comes out a lot and BLACK. There are two bathrooms on the back side of the house, where it is happening the worst, but they are not leaking. I can show pictures if you'd like to see, it's driving me and my family crazy to think there is something terribly wrong. Thanks for your help!