Published: November 15, 2008 09:24 pm            

Care needed when cleaning tombstones

Recently a few things have occurred forcing me to feel it necessary to go over the processes of cleaning tombstones whether they are made out of stone, brick, concrete or metal.

A few weeks ago, the next to the last meeting of the “Visionaries in Preservation” was held at the library, and the speaker for the program was Gerron Hite, cemetery coordinator for the Texas Historical Commission. Bruce McManus, my cemetery partner and I, have been working with Hite since the year 2000 trying to get every cemetery in Navarro County set aside and preserved under the Cemetery Preservation program started in 1996 by the Texas Historical Commission.

To date, we have completed 72 cemeteries in Navarro County, but there are at least another 100 left to do. Needless to say, when you work on this many cemeteries, you will learn the dos and dont’s of cleaning tombstones. During the meeting, Hite told the audience tombstones should only be cleaned with a very mild soap, using a bristle or plastic brush and a lot of water. The Texas Historical Commission has published a brochure on the proper methods of cleaning stones and their recommendation is to use a mild soap called “Orvus.” Feed stores may handle this soap, but if they don’t it can be ordered.

This week I called Hite and asked him if he knew any other source of information about the proper methods of cleaning tombstones. He gave me the e-mail address of the National Center for Preservation Technology and Training, which is located in Natchitoches, La. This is a branch of the National Park Service. The Web site has both a video you can watch on cleaning tombstones and also a printed version of the same program.

The program starts off with the following “dos and don’ts.”

• Don’t do anything that will damage the original surface of the stone.

• Don’t use bleach or other salt-laden cleaners.

• Don’t powerwash with anything over 300 psi.

• Don’t sand blast or use harsh mechanical methods such as power tools.

• Don’t use strong acids or bases.

Among the “dos” on the list:

• Do no harm.

• Select the gentlest cleaning method to accomplish the task.

• Do perform small test patches before cleaning the entire stone.

• Do follow manufacturer’s recommendations.

• Do follow manufacturer’s safety guidelines.

In another brochure about cleaning stones, there is a recommendation not to use any type of steel or metal brush. They even go farther in their recommendations to state don’t use a brush with a metal handle, because if it should strike the tombstone, it will leave a permanent metallic streak on the stone. On numerous occasions I have seen this problem on archeological chert artifacts usually brought about by the object having been struck by a plow.

Many individuals have the impression tombstones, whether they are made out of stone, concrete or metal, are sealed and therefore impervious to penetration by some type of moisture. This is absolutely incorrect. Most tombstones are made out of three various stones. Limestone was used for tombstones back in the 1800s. Marble and granite were also utilized. Of the three, limestone is the softest material and therefore more porous. If the polished surface on a stone has been removed either through the weathering by time or by a chemical or mechanical means, the tombstone will start deteriorating at a much faster rate. Future generations will not be able to find where their relatives were buried.

Concrete tombstones are even more porous than the stones made out of true rock. In many of the county cemeteries, Bruce and I have found concrete tombstones which are weathering badly. Many individuals’ graves were marked by this method because concrete was cheaper than rock tombstones. At the time, most people thought these concrete tombstones would last just as long.

There are a few true grave houses made out of brick here in Navarro County. Brick presents another problem if someone wants to try to remove any growth or for that matter graffiti attached to the brick. A typical brick is nothing more than a lump of clean clay which has been fired to make it into a resilient piece of building material. The outside surfaces on a brick are only a millimeter thick, and therefore can not hold up well to any form of mechanical or chemical cleaning. Once the polished surface of a brick has been removed, water will continually penetrate and pieces of the brick will start sloughing off. If a sealer is applied on a fairly regular basis, the brick will more or less be sealed and resilient to water penetration. The sidewalk and all at my house are classic examples of water penetration resulting in numerous areas where the brick is continuously deteriorating.

For those of you who would like to view the Web site on your computers about the correct methods for cleaning tombstones, here is the link: www.ncptt.nps.gov/Training/Videos/Cleaning-A-Stone-Grave-Marker.aspx.

Next week: Cleaning metal.

        

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