Rotten Food/Dirty Socks smell coming out of vent?

Lubegard 96030 Kool-It Evaporator and Heater Foam Cleaner

 

FYI, dealers have "Foam Evaporator Cleaner and Refresher" in their parts dept. I use it about twice a year in my Gen 2, which was known to have a bit of a problem with mold growth in the evaporator (design flaw).
First time I had a mechanic do it, located the drain tube, had him tie/tape a piece of nylon string to hand down from it so I could save $ and do it myself.JMO, but I think better than Lysol, which I also do not wish to smell.