Do you mean you can't start the engine because the battery has run down? If it cranks fine but doesn't start or run, that's not related to the generator. If it WILL start with a jump-start or with a charger connected, the power steering fluid may have softened the brushes inside the generator. That would prevent it from recharging the battery. Cleaning won't help that since the fluid itself isn't going cause a no-charge condition. It's the eventual damage to the brushes I would suspect.
I can't find a picture of your generator to see what is involved in the repair so if it isn't charging the battery, it sounds like replacement of the unit is necessary.