When I bought my Elise (2nd hand) the dealer cleaned it beautifully. The only way I could tell if a window was open was to poke my finger through it.
I have never been able to get really clean glass since. I have misty deposits on the inside - if I polish them off it all goes smeary again in a few days. I have tried using all sorts of proprietary glass cleaners.
How do you clean windows ??