From what I can gather its a fungus that has grown on the evaporator and although you can only see a bit of the evaporator, it has grown on 95% of it. Its also welded on pretty tight and with the fins being so delicate I'm kinda stumped on best method to clean this as obviously to much water and chemical means it will run inside the car. Now I'm not bothered about the carpet getting wet as that will be removed and I can mask off and remove most of the electrics that are near by, but just unsure if air and chemicals will remove this.

Any thoughts?