Anvils allow you to rename items, repair enchanted items, and even combine the enchantments from different items, at the cost of experience points. Crafting. You'll need 3 blocks of iron, plus 4 more iron bars, for a total of 31 iron bars.
Passivation is the treatment of the surface of stainless steels, often with acid solutions (or pastes), to remove contaminants and promote the formation of the passive film on a freshly created surface (e.g. through grinding, machining or mechanical damage).
Passivation only removes free iron contamination from the stainless steel surface. Pickling, on the other hand, removes surface iron contamination, heat tint and weld scale. After Pickling, it will produce a dull matt uniform grey finish on the metal that is the effect of chemical micro-etching.