I think engraving and polishing must be the oldest metal-finishing trades.
Having seen decorative metalwork as early as Bronze-Age in Dorchester Museum, I woinder if they used metal tools or flint gravers?
A couple of years or so ago the Dorset Echo published a photo of the back of a bronze mirror, decorated with dozens of overlapping scallop-shell patterns. Accepting a newspaper's normal photograph definition is not as fine as a standard photographic print, looking at the image of the mirror closely you could see the tiny irregularities in the spacing and curves of the shell ribs you'd expect from hand work with what to us would be crude tools – but none had slipped over the borders.
If anything those tiny imperfections stress this was the patient hand work of an unknown craftsman or woman millennia ago, working with this up-to-date material with so many practical and aesthetic possibilities.
I don't know where it is now, but the mirror's structure is a very elegant circular reflector on a handle composed as I recall, of a row of three toroids.
It's interesting and rather awe-inspiring to see that the decorative work of many otherwise functional items made now, still often uses motifs developed hundreds or even thousands of years ago, as the second of Gary Wooding's photographs show by all that Celtic knot-work.