Suitable safe cleaning solution for aliphatic urethane I am looking for a suitable cleaning solution for a sprayed on coating that is an acrylic aliphatic urethane. My end goal would ideally be something that can neutralize rust, whiten and brighten the surface, and also include a powerful enough solvent that can loosen stuck on dirt/soap scum but not harm the urethane.

The urethane is approximately 70% solids (don't know if that matters or not). I'm not a chemist so layman's terms would help greatly.
Oxalic acid is good at removing rust (iron oxides) and generally not agressive against polymers like polyurethanes.
Chemical resistance of polymers is however a complicated area, because polymers comes in a wide spectrum of formulations, additives etc. Some indications can be found on different manufacturers websides