Recommended electrical cleaner for a SoM gen clean

[Ciderman]

Hello you lovely people,
I have a very good condition 2.5kw 6/1 SoM set which has what i would call a normal amount of dirt, oil/grease and dust collected in the alternator innards.
I was thinking of using some standard electrical contact cleaner to wash it with in-situ, but im wondering if there is a recommended cleaner that won't affect or damage the shellac and elderly rubber wiring etc.
Ideally I'd like to give it a good wash out, blow it clean and try to run it, and see if it makes any volts!
Any hints or advice is most welcome.