I've heard that some stuff can damage things like the cleavises, make landing gear brittle or whatever. Never had any problems. What I use is wind shield washer fluid. It works great. Get a gallon of the stuff for under $1. Put it in an old windex spray bottle and you are good to go. For a really clean job, like recovering, decals, or cleaning engines, I bust our some isopropryl Alcohol(rubbing alcohol, sorry I'm a computer enginnering major, not English or Chemistry), and it will really cut through the grease. Wind sheild washer fluid in my opinion is the best.