Go to local hardware or even grocery store and get some Zud cleanser. It's for rust removal and works great.
The other efforts you are making may cause more problems, vinegar is a corrosive.
Re: The Nightmare of Rust: Elendil's Helm
2"and I have filled him with the Spirit of God, with skill, ability and knowledge in all kinds of crafts- to make artistic designs for work in gold, silver and bronze, to cut stones, to work in wood, and engage in all kinds of craftsmanship"