I think the absolute definitive way to do it is with electrolysis. This is where you place the rusty component in an electrolytic solution (can be water with a salt dissolved in it) and run a current through the rusty piece and a "sacrificial" piece of metal via the solution. It works similarly to electroplating but instead of depositing a coating on a metal, it removes the rust. I've never done it and I think it's a bit of an effort to set up the first time, but after you've made a rig to do it, it's the most effective way.
I wouldn't set this up if I had just one piece to do, but if I had say 5 items to do and they were fairly rusty then I probably would. One of the major benefits is that this can be used for VERY rusty tools, cast iron pans, etc. and does not damage the "healthy" metal underneath the rust. It also doesn't require any harsh chemicals or hard scrubbing.
There's an example here http://www.instructables.com/id/Electrolytic-Rust-Removal-aka-Magic/ but if you search for "electrolysis rust removal" (without quotes) or similar on google then you'll find tons of results.
I believe that after using this (or any) method, you should dry the items thoroughly (in a warm oven can be a good way, though not if there are wood/plastic parts) and oil them to protect from further rusting. This is especially important if working on cast iron (use vegetable oil if the items are cooking utensils/pans) as this will rust very quickly if not dried out and protected.