Hi Steph, I read some time ago that using pieces of Styrofoam chunks (like those that come in large packages to hold items steady) to rub over stones that are covered with moss and lichens would work without being nonabrasive. I have to tell you that my husband and I decided to try this on some ancestors' old spire like monument up in RI that was put up abt. 1898. We couldn't read 5 of the 6 names inscribed plus decorative detail due to it being covered with lichens and moss. We rubbed the whole monument with the Styrofoam chunks that made the lichens just roll up, then periodically poured gallon jugs of water over our work just to keep rinsing off debris. Then we both used soft bristled brushes to gently rub around all the names and letters that were filled with moss also, then repeated the whole process again with the Styrofoam and water. We ended it all by lightly spraying a fine mist of Tilex for Mildew on the worse parts and letting that spray air dry so as to kill any remnants of moss. I couldn't believe the improvement!! We did this last year and I must say the monument looked brand new when we finished and still looks great as of 2 weeks ago. The caretaker even came over to see what we were using and couldn't believe the 100% improvement with 45 min. of work by us. I now carry a little plastic bag in my trunk with Styrofoam, brush, and tilex. Just add water to an old milk jug and you're good to go! Good luck. Joan In a message dated 1/23/2004 1:02:20 PM Eastern Standard Time, stephaxi@mindspring.com writes: Hello....I am requesting info on the best /safest way to Clean very old Marble Tombstones. Thanks for any help Steph Powell Cecil stephaxi@mindspring.com