Unfortunately, I don't have a 'before' picture, but the entire interior was coated with thick, black carbon and oil similar to what you can see in the lower intake here:
I soaked the upper intake in a tub filled with one gallon of Simple Green, then enough hot water to submerge the intake...
I see a lot of people balking at the idea of soaking their upper intake in Simple Green, saying that it attacks aluminum. So I did a test, then forgot to post about it. I put a section of 1/8" thick aluminum into a container of undiluted Simple Green on 4/19 at 5:44pm. I used a Scotchbrite...