[TheForge] copper patina

[PlumDon at aol.com]

I know we have been here before but cant seem to find my notes on it. 
 
Can anyone recommend a technique for putting an aged patina on copper?  
Looking more for the brownish, rust color of an old penny rather than  verdigris. 
Any ideas much appreciated. 
 
Re last weeks question regarding forging copper I have found the more pure  
the copper the better to forge. I annealed at a just red heat and cooled in  
water for the thinner stock. Heavier stock worked great from low red to cool and 
 hard to shape. 
 
Kindest thanks
Don Plummer