How,do,I,remove,engraving,from,a,5th,gen,iPod

I doubt you can. Since engraving involves removing metal you would have to file down the entire back of the device until you had removed a thickness equivalent to the depth of the engraving, Probably a jeweller or a metal worker could do this, and polish it, but I don't know how deep the engraving goes compared to the thickness of the back, and it might very well weaken it too much. You would have to ask for advice from someone equipped to do it.

I would get some spray or marker the same colour as the ipod and go over it rather than trying to remove it.