If you'll buy a microfiber polishing cloth from the auto parts store it's the best thing around for getting the stuff off. I can actually get all the crud off with no cleaner at all, although the spray bottle makes the job go faster. The microfiber rag gets 95% of the oil off on the first pass, then I go back with some windshield washer fluid and alcohol to get it out of the crevises. The airplane isn't even greasy afterwards.