>From another list-this is interesting! For YFI From: "Gail Meyer Kilgore" <gkilgore@primenet.com> Subject: [CO-CEMETERIES] CLEANING CEMETERY STONES Date: Tue, 12 Sep 2000 13:19:31 -0700 For your info: Subject: Cleaning Stone by John Dennis Cleaning Stone Check the stone's condition before cleaning No stone should be cleaned if its condition is questionable: A stone with a friable or "sugary" surface, A stone with a grainy surface that readily falls away, or Any other condition that indicates that the stone is delicate, brittle, or otherwise vulnerable. ALL surfaces of the stone should be checked. If there is Any question as to the stone's condition, DO NOT attempt to clean it as the surface could be irreparably damaged in the process. The Cleaning Process 1. Mix a solution of one heaping tablespoon of ORVUS® (a detergent that comes in either liquid or paste form) to one gallon of clean water. ORVUS® is commonly used in association with horse and sheep husbandry and is available from feed stores; 2. Pre-wet the stone thoroughly with clear water to make sure the detergent solution will not be absorbed directly in the dry stone; 3. Thoroughly was the PRE-WETTED stone using NATURAL BRISTLE, WOODEN HANDLED BRUSHES of various sizes. The use of plastic handles is not recommended as color from the handles may leave material on the stone that will be very difficult to remove. 4. BE THOROUGH. Wash all surfaces. Rinse thoroughly with lots of water. Remember! DO pre-wet the stone with clear water prior to cleaning, and keep the stone wet during the entire washing process. DO NOT allow the detergent solutions to dry on the stone while cleaning. NEVER use abrasives, high pressure washes, acids or bases, solvents, household cleaners, wire brushes, or sand blasting or other blasting equipment to clean stone! Cleaning Marble and Limestone When cleaning marble or limestone, one tablespoon of household ammonia can be added to the above mixture; this will help remove some greases and oils. DO NOT use ammonia on or near any bronze or other metal elements. Lichens and Algae Lichens and algae can be removed by first thoroughly soaking the stone and then using a wooden scraper to gently remove the biological growth. This process may need to be repeated several times to remove the material. Stains Some stains in porous stones cannot be removed. DO NOT expect the stones to appear new after cleaning. Frequency of Cleanings DO NOT clean marble, limestone, or sandstone more than once every 18 months. These types of stones may occasionally be rinsed with clean water to remove bird droppings and other accretions. Granite can be cleaned as needed. Keep a Record of the Cleaning Simple treatment records should be kept with the date of cleaning, materials used, and change in condition since last cleaning (such as missing parts, graffiti, and any other damage). These records should be kept at a central location where the condition of the stone can be monitored over time. Developed from data Supplied by John R. Dennis Dallas Museum of Art Conservation Lab, March 1995 Gail Meyer Kilgore Casa Grande, Arizona