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).
Pickling lightly etches the stainless steel. By removing material it removes weld scale and debris that may be embedded beyond the reach of passivation. Passivation targets the iron only and encourages the formation of a passive layer.