heres a story, my grandfather had this old lawn tractor and it was rusting pretty bad so he used a wire wheel and just cleaned the bulk off of the framing of the tractor. now you see it dident get rid of all the rust but most. after this he used i belive non pouris paint and some roofers tar or somthing like that and thats it… now 30 years later its still not back and last summer i went out with a wire brush and out of curiousity scrapped some of that paint and shit off and the little bit of rust was still there and never got any bigger or did anything for those 30 years. yes the only sure way is to remove it all together but cover it right and youll be fine. man this post is like a novel