I do a lot of work in copper and I go back and forth between liking it most in its natural shiny state and adding a patina to it so it looks darker and aged. There are examples in the photo to the right of the copper both ways.
A lot of artists use liver of sulphur to add patina, but I don't have a source close by and I really didn't want the odor and fumes in my house. I don't have a separate shop with a ventilation system so I looked into alternative methods. After much research and discussion on various forums I decided to give the egg method a try.
Hard boil and egg and while it is still warm, cut it in a couple of pieces and put it in an airtight container with your item. I have read people stating to not let the egg touch the item, but my egg and item always get jumbled together and I never found it to be a problem. In fact, when I was using the egg method on this bracelet I squished the egg and mashed it into the bracelet. This bracelet has a very tight weave and just leaving it sitting with the egg wasn't working very well. I use a ziploc bag to do this so I can keep moving and turning the item to get good coverage.
Having never used liver of sulphur, I can't be sure, but I believe that this method takes quite a bit longer. In fact, most of my pieces get left in the egg overnight.
All the copper in my Etsy shop, so far, has been left shiny. I do indicate in the descriptions that it will darken on its own over time, but maybe it would sell better if I added the patina. What do you think? Any opinions on copper bright verus darkened?