Master cylinder questions

Hey guys and gals I have a few questions about my masters cylinder. Numer one is there anything I can put on it to keep it from rusting? I dont want to paint it as i want it to look original and i know brake fluid will eat it off anyway. I was thinking maybe spray it down with wd40 or paint it with Motor oil something like that. Has anyone ever tried that?
2nd and this may be dumb one. But can you bench bleed the cylinder while in the car? Just using the pedal plunger? I'm familiar with bench bleeding them if always done it with a long screwdriver and a vice. Plug the holes until no more bubbles come out. But wouldn't it be the same thing using the pedal? Or is it not long enough? Thanks guys.