In after mid-dec 09 snowfall. My car, which is Ibis white was black and mucky as anything! So decided to spend 2 days cleaning it.
Lessons learnt: Don't wax it in freezing, winter conditions. For example when the evening gets cold and moisture forms on the roof as it makes it a nightmare to remove! Had to buff it off in the garage after spending 40 mins hair-drying the roof!

These were the results;