I think I asked about this before...but couldn't find it. My western outside walls tend to be WET on the inside. (concrete block - stucco outside, paint over plaster inside). I mean REALLY wet - sometimes drips forming...and black dots of mildew. They're pretty easily cleaned - I've been using hot water, white vinegar, with a little soap. I don't think there are any easy solutions (or cheap ones), but if you all have thoughts on it, I'd love to hear! It's worse where peices of furniture are against the walls (although the mildew also seems to like to travel up corners, and a bit along the ceiling in the corners of the rooms). I'm going to be pulling everything out about 10 inches and leaving them there, and occasionally aiming a little blower/space heater along the walls to dry them off so I don't have to move things and scrub so often. DH wanted to put a dehumidifier in the crawlspace under the house - but I think those might be expensive to run, and not sure how effective it would be down there.