D.D. asked, "The dish detergent thing sounds messy. Do bugs stick to it. I wondered how you apply it. Can you water it down and spray it on?"
No it's not messy, I simply put a few drops on a small sponge, or a wash cloth, or even a bit of paper towel. Then I wipe it over the inside of the windows, using only enough to dampen the glass; it's so thin you don't even know it's there, but for the fact you can then see through the window because it's not fogged up. You don't use enough to make bugs stick to it, and when it warms up enough in the cabin, you can wipe the windows with a cloth containing only clear water, but you really don't have to because the windows dry clear.