I farm up here in Canada and use a lot of granular fertilizer products, I've found unless both sides of a seam (where stuff bolts together) are perfectly cleaned and sealed that the rust can actually blister worse if you only seal one side of the join. The best thing I've found to counteract fertilizer/road salt (very similar) is fluid film like another member mentioned. It's also safe for paint, electrical and rubber which kerosene and diesel are not (also smells better imo)
Sent from my iPhone using Tapatalk