I just finished watching the Patina Basics by Tim McCreight. He used items that you can find at home that are safe to use. I got it at amazon.com and it was worth the price. I made a Christmas tree ornament out of copper for my roommates and I want to steal it back and play with some patinas to make it look better. lol If you can afford it I highly recommend getting the DVD. I don't know if a library would have a copy of it, but it would be worth checking if you can't or don't want to buy it right away.
I made an ornament out of copper for my roommates. I tried to acid etch, but the acid didn't cut deep enough so I opted to try the ammonia and saw dust patina. The ornament sat for a little over two days in the mixture. I washed it and put a couple of coats of laquer on it to protect it. As you can see, I need to work on my stamping technique.