I must admit i'm a little confused, i didn't use 'Gunk' which is a cleaning agent, i used Jenolite which is a rust convertor (basically a type of phosphoric acid which converts Iron oxide to iron phosphate, it leaves the surface black with white powdery deposits.
You appear to have used just a cleaner which will leave a residue all over the area cleaned the metal looks good so id say you've caught it well in time but you'll still need either something to treat the surface for rust like jenolite then give it a good clean, or carb cleaner to get rig of the residues of gunk and then an oxide primer
if not done properly you'll be wasting your time the paint won't stick and the metal will carry on corroding
You appear to have used just a cleaner which will leave a residue all over the area cleaned the metal looks good so id say you've caught it well in time but you'll still need either something to treat the surface for rust like jenolite then give it a good clean, or carb cleaner to get rig of the residues of gunk and then an oxide primer
if not done properly you'll be wasting your time the paint won't stick and the metal will carry on corroding