I use vinegar a lot for cleaning up rusty steel parts. Don't use on aluminium parts. It takes time, sometimes a long time, but it always works. Give it time, vinegar ALWAYS works.
Then give the parts a wash with water. Then I mix up some strong bicarbonate soda in water in a spray mister bottle and give it a good coating until it drips off. This is not really necessary but it basically just neutralizes any left over acidity from pits and crevices. Rinse off again with water.
Next I wipe down the object thoroughly with straight methylated spirits on a cloth. This always works for me. Any remaining rust gets wiped off.
Then before any flash rusting has time to re-appear, I spray the whole thing with rust converter. After that you can put on a primer, then put the enamel straight on. Anyway this is what has always worked for me.
