Does anyone know the best way to remove all that old gunk from the evaporator and fan box and from around other areas of the firewall? I am trying to prep it for paint and just throw a nice coat of primer on it so its protected until i get more body work done and ready for paint.

 

A heat gun or propane torch and a scraper would be about the easiest way.

 

And probably a can of elbow grease....
Mine came with out all the plastic bits and I waited until the engine and hood were not in the way. It still took about 2 hours to make a noticeable deference.