I tried a pickeling solution today. I wanted to try the most none toxic and least expensive, so I tried a solution of vinegar and salt. Apparently the acidity of the solution will eat off the oxidization and fire scaling off of the copper. I used 1 tablespoon of salt per cup of vinegar. I let the vinegar heat up, added the salt, stirred till the salt dissolved, and then added the birds. I left them in for about a minute and a half and then took them out and scrubbed them with a tooth brush. They came out slightly better, but not drastically. There is still a lot of oxidation and fire scaling left on them. I plan to try the solution again and leave them in longer. I didn’t have enough time to try today.