I used the Eastwood "brush-on" stuff 3 years ago on mine and they're solid rust now!!!!! And I did know how to properly prep them!
When someone mentions "Eastwood" to me, I immediatly think of a $1.98 can of spray paint for $9.00, ! (plus shipping) ! OK, big deal - they put their own label on it so it cost them about 85 cents..........total.