Video: Which works best at removing rust, CRC Evapo-Rust, sand blasting or a wire wheel?

Phosphoric acid will resolve iron oxide ( rust) away without attacking the metal. Also small amounts of this is found in either Pepsi or coke. 

It's major use is to apply a thin oxide (anodizing) to the surface of aluminum alloy for bonding of aerospace parts. 

SolGel chemistry these days offer highly inert coatings to metal that is impervious to both h2O and  salt ions. But its micro thin so it needs a paint layer to continue the protection. Standard chromate primer is used with aerospace parts. The chromates being the nasty one of the bunch , quite toxic in general. 

In reply to Noddaz :  yah liked the part about the guitar calluses and being gone faster than the "ouch"

somewhere behind some old benches is some british whitworth bolts lost during wire brush cleanup ( using a grinder w wire brush )  Some may even have bits of dessicated skin on them LOL

In reply to 20Ver :

The rust removed the zinc. If all one does is remove the rust then it will rust again. It must be replated or given some sort of protection, ie paint. There are diy plating kits.

In reply to RonPNW :

Diy plating kits are available if you wish to retain original hardware.