I ran my finger over the surface of the inside of my processor after emptying it & it came away covered in a greasy residue which had lots of small to tiny specks of dirt in it. Looked a bit like I'd applied a lot of ground pepper to the inside walls.
I tried washing it off with the hose & cold water but that did v. little, the power washer blasted it off the sides pretty effectively. The water run off was filthy with a surprisingly thick layer of brown scummy stuff on top.
It's pretty easy for me to clean mine as the lid goes up but, if mine was that dirty after only a few batches this spring (I don't make fuel in the winter) then I wonder what the inside of sealed GL type processors looks like?