Hey I know what you mean about zinc chloride, that is what amazes me about the body...if I took hydrochloric acid and put it on metal or wood it would burn a hole through it, yet every day our parietal cells make and excrete it into our stomachs to break down protein. Different tissues in the body can handle different chemicals, thats why many people have taken black salve internally over and over and had no problems, although I still would tell everyone to try it, I am merely stating that it has been done many times with good results.