We don't have central air and our home was built in the 60s (and updated very little since then) so we have a few areas that smell really, really musty, especially on hot days. I've bought a few air fresheners but I'd really love to get rid of the source.

I think the smell is probably traveling down from the attic because our dryer and bathroom vent from upstairs were improperly venting into the attic until we fixed that when we moved in... the strongest smell comes from the upstairs bathroom (in particular, a closet in that bathroom), the laundry area next to the bathroom, and our newly gutted and renovated kitchen... but just the corner directly under that area, and especially when we're running the vent fan.

After some googling I think the real answer is to run a dehumidifier FOREVER, then paint. This would be a huge task since our attic doesn't have a floor to stand on!

Any other ideas?