Aughhhhh!!!! Mice have been storing dog food in my 92 Honda Accord through the winter. I have removed as much as I can with my shop vac but I'm sure there is more. any help will be appreciated. I'm getting sick of of the dog food smells coming through the vents!!

 

Wait lol, mice have been using your car as storage for dog food? I've never heard this one XD.
Try febreze in the vents and the intake vents.
Or at advance auto they have this product that you spray into air vents to get smoke smell out and what not, try that.

 

Its strange the debris has made it past the evaporator. Its a good bet your blower box is full of dog food. You should remove the blower and evap cases. Clean them out with soap and water. You can disassemble the evap case and clean each piece separately. Tape off the suction and discharge ports on the evaporator and submerge the evaporator in a bucket of hot, soapy water. When the evaporator is out, you can reach into the heater core and pull out more debris. When you reinstall the blower box, it will be a good idea to fabricate a screen on the inlet of the box. Use a high quality material, something that rodents cant chew through. Rabbit screen should work. Once its altogether, the increased air flow should help push out any remaining debris. Use "heater" function, let gravity help you. If all that fails, the dashboard will have to come out. Good luck.