There are several related topics here.
1. to prevent rust on new, fresh metal, you prevent oxygen from getting to it. Best is a zinc rich primer, epoxy, then urethane/acrylic for sunlight exposure (if necessary).
2. for short-term rust prevention on new, fresh metal, most rust preventers are simply mineral oil in a spray can
3. you can make "fancy" mineral oil in a spray can and want a little bit of rust-neutralizing action, you add an organic acid, like oleic acid, to your mineral oil spray can
4. longer term rust prevention storage, try some wheel bearing grease or thick motor oil (e.g. machined block, crank, etc)
5. to truly neutralize rust, you need a stronger acid and phosphoric acid is preferred. After reacting with rust (& literally removing it), a byproduct of that reaction is iron phosphate...which is moderately effective rust inhibitor coating, so you get a 2-for-1 action with phosphoric acid.

For me, I cut out all major rust. Then I brush in a phosphoric acid 1-component "rust neutralizer" like in most parts stores to get the tiny lit pits of rust neutralized (note: sandblasting is way better). Epoxy over everything. If exposed to sunlight, polyurethane primer on top of that......then paint as needed.