<HTML> . . . . . . I am not sure about this but if you let rust on the strings, wont that block the atmosphere from attacking the surface and prevent further new rust from forming?...or....does it work the opposite?  that is, if you take the rust away it will inhibit any more from forming??? I ahave always wondered about this.Thanks, Julia GottshallReadong, PA This works on aluminum and silver, but unfortunately not on iron or steel.  The reason is the oxides of aluminum and silver are insoluble and not permeable, but oxide of iron is both soluble and permeable.  So just the free oxygen in the air, especially along with humidity will easily penetrate the existing rust film and find its way to the unrusted iron underneath. For steel products, a treatment of phosphoric acid is often used to prevent rusting.  A surface of iron phosphate is developed.  This doesn't have the strength or ability to rejuvinate itself like aluminum oxide, so it must be painted to give long life, i.e., auto bodies, refrigerators, etc.  Otherwise a plating such a chrome, or a mixture of metals such as stainless steel can be used. If the piano industy were multi-billion or needed for defense, research might be able come up with a viable rust-free piano string. Loren Hedahl</HTML>