If it's a Wagner it's pretty good,if it's a Griswold it's the best.

First you card off all the surface rust you can with a single edge razor blade.

Then you can either use sandpaper{by hand or random orbital} begin with 100 grit and finish with 220.

I prefer using a scotchbrite wheel but most hobbyists don't have access to one.

After sanding use a soapy brillo pad or 2 with a circular motion to remove any remaining corrosion that may be hiding in pits,plus any metallic particles left over from sanding.

Put it on the burner at medium high,wipe it with cooking oil and let it smoke away,do this a couple of times'til you have a nice "seasoned" surface.

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