G'day Blue victor, I have tried a few different cocktails over the years. Heavy coats of deodorised fish oil is probably as good as anything, however I have used a tar base mixed with fish oil and thinned with GP thinners so I can spray it in and get it to flow into all the cavities, but very messy until it all dries. None of my cars have had any rust or flare up over the years, But they don't stay out in the weather either and don't often see rain days, just the hose from regular washing. You must make sure the arears you want to treat are clean and don't have rubbish and dirt build up or the dirt will attract moisture and rust under the rust treatment.