If it's oxidative damage to a metal, alcohols are not very good solvents for that. Water + surfactant/detergent is better. I wouldn't try to get too deeply into the chemistry. There are basically two choices water-based and non-aqueous. IPA and ethanol will both have some water, unless you use absolute versions or something like E85, which I do not recommended, but I would consider those alcohols as non-aqueous. Glycol ethers that are in all of the aqueous flux removers have special solvent properties. Using an aqueous flux remover is generally safe and a good cleaner even if flux residue isn't the issue.
There is nothing wrong with starting with IPA, though.