Yes I do my set up and take apart outside, but the ammonia is very contained, you only need about 1/2 inch in the bottom of a jar. It works really well for Brass and Copper. It takes a couple of hours, Less if I remember to wash the metal in soap and water first. I am sure Liver of Sulphur is quicker and more commonly used, I just like the idea that I can do this cheaply and anytime I need a certain type of wire oxidized without having to pick up any special supplies. I am still home on this medical leave with time to experiment. Thanks Wanda