Over the weekend I left some copper and brass test pieces in an airtight container in tobacco dampened with ammonia and vinegar 3:1 parts. This was to patinate them to a turquoise blue colour. Here are some photos of the pieces, where the colour took it looked great, but I as looking for a more even coverage. I did find however, that the solution ate away at the metal ( not sure if it was too strong?) but it created some interesting effects.