User blog comment:Fairy Tail Grand Master/What is the hidden blade made of?/@comment-1889286-20120628173035

I read in a book once that you can strengthen metals by forging it, grinding it down to "metal dust" and mixing it in with chicken (or some other bird) excrement and reforging it. And the more you do this, the stronger it gets. It's something to do with the gases in the excrement, apparently. However the book was fictional, so I'm not sure if this is true.