There are hundreds of Chemical Patina Recipes; many requiring expensive, hard to find and potentially dangerous Chemicals, all things I like to avoid whenever possible. Instead, my favorite Patinas are made by more common household chemicals. My current favorite household patina, is a brilliant blue made by using:
1. Clear Ammonia (found in the cleaning aisle of your local grocery store)
2. Table salt
Step 1: Making a fume chamber
At the bottom of the fume chamber place a bit of paper towel. Dribble some Ammonia on it; you want it moist but do not soak it. Warning - inhaling Ammonia fumes can be harmful.
The Fume chamber is now ready for use.