I have a problem with some rats that moved into my ventilation system while I was on deployment. If I ever take my fan off of recirculate mode it smells like rat urine inside my car. I need to get in and clean it out as best I can, but I don't have the time to really dig into it if its a bigger problem than I think. How difficult is it to access the ventilation interior so I can clean it all out?

EDIT: So I dug into this today. Going to be quite the clean up. after getting the blower motor off I realized how much of a pain this is going to be if I can't remove more. Anyone know if its possible to remove some venilation ducting without removing my dash? Seems doubtfull looking at it.