I use Simple Green Extreme Aircraft and Precision Cleaner. It is meant for aircraft use so when diluted properly will not etch or destroy the underling materials. From their ad
New aircraft and precision cleaning product, cuts through tough, built up grease, oil, dirt, pollution, insect residue and impact soils
It causes no harm to aircraft structural metals, plastics, paints, or coatings
Documented conformance to variety of aircraft testing specifications. Safe for use on aluminum, carbon fiber, and more. The components of extreme Simple Green are all low-toxicity compounds and the product contains no "solvents"
I use at 7 to 1 ratio.
Bob