I've recently read about a couple different methods for patinas - I have have not yet tried these, but I'm hoping to do some tests with them in the next few days.
1) The elusive (for me anyway) verdigris finish on copper. This is a new one - 1) Spray your piece with vinegar. 2) sprinkle salt on your piece. 3) Suspend your piece in a container with about a 1" of ammonia in the bottom. Your piece should not touch the ammonia. This method supposedly creates the blue/green finish in about 24 hours. I will post results as soon as I get a chance to try it out.
The next tip helps colours pop in liver of sulphur.
When preparing your LOS solution, add in 1 tablespoon of ammonia.
A word of caution if you have never used straight ammonia before. DO NOT BREATHE IN THE FUMES. Use in a very well ventilated area ONLY.