I would like to ask a question about how to maintain (clean-up corrosion) on a vintage Mac logic board. Is this question OK?
Sure. While corrosion is a general issue - not only with cars but as well in electronics - handling it is even more essential with classic machines. In fact, old computers feature additional angles to this than the corrosion itself, like how to handle rare, no longer available components or when does sensible removalof corrosion and 'dirt' turn into destruction of history.
So, if your issue hasn't been asked for by now - doing a short scan is always a good idea - you're very welcome to add it.