You can pick up a can of a/c coil or fin cleaner at most hardware stores. They are no more than degreaser/cleaners such as Simple Green. All you need is something that is aluminum safe. Spray it on and hose it off. Good for a/c coils and engine radiators.
Jerry & Judy, Fremont, California
2017 Dutch Star 4018
Freightliner, HWH Active Air