Like many of you I am a maintenance freak when it comes to things with engines and wheels. I am super regular about cabin filter replacements and am also careful not to let too much organic debris collect in the windshield cowl area. The vehicle gets a thorough driveway bucket wash once a month which means the cowl drains are flushed clean with soap as well. Well despite all this, I got the nasty mildew odor in the HVAC system after running the AC. In the past, I have been able to address this early on by drying out the evap coil with the fan on HI and AC off, but that trick stopped working. I picked up a can of this FJC stuff off amazon and finally had time today to try it out. Per the instructions, you are to snake the vinyl tube into the evap drain tube and then depress the can top, filling the entire "system" with the foam. It will then clean the dirt and drain back down the evap drain tube. It's then recommended to wait 20 minutes for a complete draining and then to run the HVAC fan on HI to dry out the coil. I found that the trick is to block off the evap drain hole with your hands or a rag (while the vinyl tube is in there), which allows the propellant in the can to shoot entirely into the system. I pretty much emptied the entire can and then let it all slowly drain out. Got into the cab, turned on the key, and was IMMEDIATELY greeted with the windex type smell of the product for a minute or two and then just clean fresh air. Smells like factory new for the most part and could not detect any more mildew odors. The stuff is pricey at $15 per can and I could not find it locally, but it does work and does not have any artificial scents that stick around. The ingredients were mostly propellant, alcohol, and water, so I didn't see anything that would linger around inside the evap box or cause corrosion there. I'm hoping whatever i cleaned out was a one time thing and I won't have to repeat this, but it's easy enough and beats trying to odor bomb the system with lysol cans or whatever else people usually do for this.