Have you opened the door? Taken the panel off to see what's inside? There might be something wicking moisture and then giving it off. Good point on the plastic vapor barrier too. Sounds intriguing. Tom Very strange. Have you looked at whatever this "dust or frost" is under a magnifying glass or microscope? Is there anything different about the storage unit wall nearest the driver side as compared to the passenger side? Do you know if the driver side door is lacking the moisture barrier plastic? Have you removed the driver and passenger side door panels to look for differences internally or perhaps with the panels themselves? Perhaps the driver side drain holes are plugged and you have water in the doors and the "dust" is a fungus? I realize I didn't answer your question, but maybe these questions will lead you to answers... Good luck, Jason Wayne Huseby wrote: > What is it and why? > Just got back from the storage unit where i keep my car in the winter > and let it run for a while. Here is my question. > It is a 64 polara and since it has turned cold +25 or colder my driver > interior side door panels have turned from black to almost a light dust > or frosty color, this also happened last year (my first year with the > car). Still black underneath, they cleanup great in the > spring but as it gets cold they almost appear dusty or frosty. It wipes > off somewhat when cold. Like I said earlier, only on the drivers side, > front and rear. > > Any thoughts on this? > Puzzled in North Dakota > > > Wayne Huseby > 64 polara 500 2dr ht > > ---- Please address private mail -- mail of interest to only one person -- directly to that person. I.e., send parts/car transactions and negotiations as well as other personal messages only to the intended recipient, not to the Clubhouse public address. This practice will protect your privacy, reduce the total volume of mail and fine tune the content signal to Mopar topic. Thanks! '62 to '65 Mopar Clubhouse Discussion Guidelines: http://www.1962to1965mopar.ornocar.org/mletiq.html.