Hello, There seems to be other ways to clean gravestones ... Starting with water. _http://www.kodak.com/global/en/professional/products/chemistry/bwFilmProces sing/photoFloSolution.jhtml?pq-path=14039_ (http://www.kodak.com/global/en/professional/products/chemistry/bwFilmProcessing/photoFloSolution.jhtml?pq-pa th=14039) _http://www.rootsweb.ancestry.com/~inpcrp/repairtoolbox.html_ (http://www.rootsweb.ancestry.com/~inpcrp/repairtoolbox.html) Joan