The State of Indiana has a department (paid) charged with graveyard and tombstone location and restoral. To my knowledge their practices are recognized as the best known, as of now. I read a long story about their work about four years ago, and was greatly impressed. My recollection is that they readily share their data on techniques, etc.. Unfortunately, I lost their website information, and don't know just how to go about locating it. Perhaps some genealogy buff in Indiana will see this and let us all know more about the Indiana Department of Graveyard Location, Restoral and Preservation practices, and how we might contact them. I do know from a little study of geology and chemistry that you can do a lot of damage if you don't know what you're doing. What's truly unfortunate is that most of these "home-cures" leave such a vast improvement that people go about applying them to a lot of stones. A few years later the final effects of these good intentions show up as disasters. Jack Hurst