Well, I just did the maiden on my Sig Four Star 120 and am breaking in the Evolution 26cc and ended up with black sooty smudges and specs all over the right hand side and wing. I tried to use windex and I just smeared the stuff around. Being a bit of a gear head I always have Gojo hand cleaner in my garage so I tried it. It works beautifully! Cleaned of that crud with virtually no effort. Just sharing a tip I stumbled on.
bug and tar remover will work... so will 409, or acetone
As does Coleman fuel or mineral spirits paint thinner. My favorite is mineral spirits as it isn't overly flamable and it cuts the petroleum residue very well.