Last night I was ready to put the plastic sheeting on the windows and when I came to this one (our bedroom) I removed a heavy quilt my husband had put up to buffet the cold. What I found was horrifying: MOLD! You can't really see it in this picture too well, but there was mold on the glass as well as on the wood.
I decided to wait until today - after we did home school - to clean it. I filled an ice-cream bucket with hot water and ammonia and washed down the window as best I could. Then I washed the glass with Windex, spraying a bit here and there on the frames. After letting it dry a while, I went to work with the sheet plastic.
We use the Frost King window insulation kits that you apply to the inside of the windows with sticky tape. Then you blow dry it to shrink it fit. I decided to keep the blinds closed when I covered them.
You really can't tell that much that there's plastic on there until you realize you don't feel the wind blowing in any more.
When the weather turns warm we'll have to paint the window frames.