Paul- I just stumbled across this thread, and although it's a little late now, you might find this interesting info: one of my brothers has a turbo prop plane, and the jet exhaust on both sides was a nuisance, for sure. A mechanic buddy of his turned him onto a protective coating, wax, whatever you want to call it, named ReJex that's made for such apps. I helped him apply it, and when I saw the bottle start sliding off a barely (almost level!) tilted wing surface, I got impressed. I got a bottle, and it seems to work really well for my cars. Not as well as avoiding the problem to start with, but maybe it would have other uses for you? The picture might be hard to see, but there is a big exhaust on each side, behind the prop. The black streak used to go down the whole side, and now that it's Rejex'ed, hardly anything, and it cleans right off, whereas before it was hard to polish off.
Flying can be expensive- he got hit by lightning over Florida, and it took 8a while and well over $140,000 to get the plane back in the air (new prop, engine service, avionics, you name it had to be checked, replaced, etc.) I wonder if his insurance will go up?
