I had a old pair of my long dead grandpas. I put it in a pan and covered them with oil, checked back in a week they worked like new.

Just a week ago I found 2 brand new rotors for my van, they were on a top shelf and rusted from a leaky water pipe, copper that developed a pin hole.

while I pondered wire brushing them my girl friend immersed them in a pan covered each one with vinegar. Wierdly ALL the rust disappeared, although the once rusty areas had a mottled look. So I used a scothbrite pad on them. they looked brand new

and worked fine on the van