Bob, My description of "dissolving" was probably to strong. Etching would be a more appropriate term. I few years ago I was part of the world's largest aviation R&D facility. I met a few chemists (mad scientists) there and got a quick lesson on what happens when you leave a particular form of distilled water in a glass container. over time (a long time) it etches the glass. Mind you, we had our own distiller and then it went through a process to generate the two forms. Thought you'd be curious.

Cheers.