jewelers use dilute sulfuric acid in there pickling solutions to brighten cooper.
look for sulfuric acid drain cleaner. It will be wrapped in plastic at Ace or HD lowes. it should say 98% sulfuric acid. from what I read on this
(pickle)its about 10% acid the rest water 1:10 ratio on acid to water.
(always add acid to water ESPECIALLY WITH SULFURIC)
Try it on small lot with a small amount of acid solution.
If I were to do this and had a reason to. I would set up my turkey fryer and use a big canning pot to boil water in then I would make my acid solution
(always add acid to water ESPECIALLY WITH SULFURIC) in a 5gal plastic pail and put it into the hot water and let it heat up. when its warm around 80-90 degrees I would dip in some cooper and let it sit till all is clean. first rinse it in water then rinse it in a weak solution of lye and water then clean water again and again.
Just a warning sulfuric acid is a nasty unforgiving acid when concentrated and still nasty diluted. look up sulfuric acid burns it will eat through your skin in no time. diluted it will burn were gloves and eye protection. It will also do some pretty good work on your clothes so where the ones you were throwing out. I like to use those plastic rain suits for stuff like this.
Metal Studio Workbook: In a pickle. All about pickling solutions and how to dispose of them.