Mechanical abrasion removes corrosion and pitting. Chemical treatment stops the corrosion and removes the harmful bits, but leaves the pitting and harmless components behind, requiring abrasion to remove it.

If you are going to restore a steel *anything* NOW, go ahead and just use abrasion.... It's needed, no matter what. If you intend to restore something "later", a chemical arrest of the corrosion is a sound move, so bring out the Evapo-Rust or vinegar (acid), followed by a thorough rinse and oiling. Both chemical methods work just fine, it's your choice as to which one you use... just make sure you rinse away the acid if you go that route. Neutralizing it might not be a bad idea either, just before the final rinse (I'd use some kind of soap, it's a base that neutralizes acids). Vinegar is cheap and handy, naval jelly is less available and less cheap in most cases, but it does come in a more viscous mix.

Regards

Kaptain "You pays your moneys and you takes your choices" Zero