RE: What is the Best Airplane Cleaner
I found that denatured alcohol cut the engine residue best of all. It's sort of pricey so I mix it with cheaper Isopropyl alcohol (50-50). If cleaning a firewall for repairs, I use the denatured alcohol straight. It also loosens up old gummy engines well.
After "degreasing" the plane, then use windex to remove the last of the residue.