At the end of the a/c season last year I noticed water coming from the furnace. I opened it up and saw water dripping from the coil. I went to Home Depot and bought some foaming coil cleaner and cleaned it a few times but it still dripped a bit. The foaming coil cleaner slowed the dripping but at the end of the season it was still dripping a bit. Can someone recommend a good coil cleaner, maybe a concentrate that I could mix and then use on the coil. I would like to clean it before the a/c season using some kind of cleaner and then rinse it with water so as not to let the cleaner dry on the coils.