Lubegard 96030 Kool-It Evaporator and Heater Foam Cleaner https://www.amazon.com/dp/B0007PHD0S/ref=cm_sw_r_apan_glt_i_8ZQJM0ZFNHJXCEQ67AH5?_encoding=UTF8&psc=1

You have to change the cabin air filter, as mentioned in this thread, but also you need to spray AC coil cleaner on the coil to remove the built-up contaminates on the evaporator. I use a product called Kool It that works quickly and leaves the AC system smelling fresh and clean for months.