Over the years I have worked with some very toxic chemicals.Encluding nitrates and phosphates in the patina of copper. Recently I have done away with these methods and have experimented with citric natural fruits such as grapefruit, lemon,limes,grapes and other natural acids found in nature. To my surprize some have work an dsome not. I aslo have worked with aluminum and find that to patina this metal even shoe polish works to some degree, but for now I am powder coating this metal. More to come on this subject.
Great tip. I would also suggest using a hard-boiled egg to tarnish silver.
Boil an egg, let it cool, peel the shell, mash it up, insert silver jewelry into container with egg over night. Seal the container.
Voila! In the morning you will have a nicely tarnished piece of silver that has a bit more character!
I tried using eggs and forgot about the boiling and blew them up. Back to aluminum.