...is that when they get dirty cleaning them actually helps. Old double-paned windows with broken seals don't look any better when you don't clean them, which gives you a good excuse for not bothering. My new ones, none of the crap is between the pieces of glass, so I just KNOW they would look a lot better if I cleaned them. Yeah, it was great having an excuse. But now that I spent the entire day cleaning the house, [2 loads of dishes - 4 loads of laundry - a full recycling bin of papers that were laying around], I'm just going to have to fix it so the dirty windows don't stick out like a sore thumb. Which means cleaning them. Bleah!