I found a rust removal product I am very impressed with. It is called EVAPO-RUST. It works as good as muratic acid (somewhat slower) but it is water based, biodegradable, and will NOT
harm paint or skin. If it harmed paint I would be up the creek, because I had a fitting leak and my tank got soaked over night. It is currently being used by the U.S. Army. It worked very well for me. I found it at http://http://www.theruststore.com.