= Ford did come up with just such a procedure to maintain the A/C system on their = vehicles, about ten years ago. The solvent that was originally used in this = type of application was Freon TF solvent. Liquid oxygen = facilities formerly used this often to assure the removal of all petroleum = products in aircraft or whatever, because of the explosive potential. Ford reintroduced this because they have a = truck that has 3 expansion valves and thus often there is not enough = force in the system to push debris out to the filter dryer. They also = recommended it for all their vehicles for whatever reason. It does = work but it is expensive as I recall.

= It is most likely the dryer desiccant that is spread through = this A/C system now, the color would indicate this is the contaminant. There are also some other cleaning systems available = for this purpose, I have seen air brake alcohol recommended for this = purpose, it evaporates and it is very inexpensive.