Jim, I did it in two steps. First, I sprayed the front face of the evaporator with some CRC Brake Kleen which did a nice job of dissolving all of the oily black crud imbedded in the cooling fins. I really flushed it good with this stuff (used 2 1/2 cans). After that evaporated, I sprayed the core with Coastal Power Cleaner, let it soak for about 20 minutes, flushed it with the hose and repeated the Coastal treatment again. Really gave it a good flush with the hose. All of the crud and water drained thru the evaporator drains. You should have seen the mess of stuff under the car. Side benefit, got rid of that funny mouldy smell that I noticed for the first couple of minutes of A/C operation.
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.