I had the good fortune to snag a Disston #12 panel saw last Saturday.  It is a beauty.  Tote is one of Disston's very best: intact with no cracks, breaks, or missing pieces. (It has one slight paint smear and a previous owner's name lightly scratched on the back side of the tote.) Buttons are clean and crisp.  Blade is nearly unused with no missing teeth and a good nib: straight, shiny and nearly free of blemishes (for a 1896-1917 model) and the etching is clear as day.
Here is my problem:  I have cleaned and "restored" many hand saws, but this saw is clearly something special.  What should I do?  My greatest concern is that I would do something to harm it.
If you can give me unequivocal sound advice, speak up. Please.  I don't want suggestions; I want to do this saw justice--if I do anything at all.

You can get rid of the paint smear with lacquer thinner.  What else would you want to do?  Mmm... Wax the blade to keep away rust.