Historic burial sites are scattered throughout Clatsop County. Most, but not all, are within our many historic cemeteries.

Some sites have vanished, or are vanishing, as nature reclaims those that lack care. Some have been vandalized, with monuments overturned, broken, and in some cases, smashed beyond repair. Ironically, many gravestones are being systematically and lovingly damaged or destroyed by those who care about them the most.

As Memorial Weekend draws near, well-meaning people head to the cemeteries to clean gravestones. Unfortunately, knowledge of proper cleaning techniques seems to be in short supply. They are stones, after all. How can a bit of cleaning hurt them?

I was in a pioneer cemetery in Grants Pass recently. The quiet of the afternoon was shattered by screeching and rasping sounds as someone was cleaning an old marble monument. The tool of choice was a wire brush with a metal scraper attached, the kind usually used in preparing a surface to be painted. In another cemetery, I saw someone with a bottle of bleach in hand, sloshing it, undiluted, over a marble gravestone. The stone was darkened with an encrustation of algae and lichens.

Afterward, it looked white. But within a year, the once-smooth surface had changed to the texture of coarse sandpaper. The one in Grants Pass had a crosshatch patten of rust stains, with rust streaks where the rain had washed down the face of the stone.

The question

To clean, or not to clean? That is the question. Before trying to clean a stone, there are several things you must know. First, is it cleanable? If it shows any sign of chipping, flaking, scaling, sugaring, or any other form of deterioration, do not clean it. You may do more harm than good. Tap it gently with a knuckle. If you hear any hollow sound, do not clean it. Nearly all kinds of stone used to make memorial stones are porous, and water seeps through the stone, flowing down through its crystalline structure. Anything the water carries with it can do surface damage, internal damage, or both.

Next, what kind of stone is it? Depending on the era, it may be marble or limestone, sandstone, slate or granite. The first three are the most fragile. Sandstone is a concretion of grains of sand, tan or brown in color, and subject to flaking and delamination. Most marble stones were cut from white marble, and polished. Bluish, gray or black limestone was used extensively for obelisks, smooth but unpolished.

Slate and granite, though harder, are still subject to damage by improper cleaning. Slate markers are usually dark, thin, plainly shaped tablets. Granite of a variety of colors has been used not only in massive, highly polished memorials, but more recently in ornately formed dies on bases as well.

The word massive relates to the cleanability question as well. Many upright gravestones in historic cemeteries have had whatever mortar or mastic that was used to assemble them deteriorate over time. They may be unstable stacks of stone, poised to topple on the unwary. Gravestones weigh between 150 and 180 pounds per cubic foot, and if they fall, they can cause serious injury or death. If the stone wobbles, do not clean it. It must first be secured, using an adhesive that will not react with the stone. But gravestone restoration is a topic for another discussion.

The most important tool to use in cleaning gravestones is old-fashioned elbow grease. There are no shortcuts that will not damage the stones. Preservation-oriented groups, including the Oregon Commission on Historic Cemeteries and the Association for Gravestone Studies, offer several precautions:

Do not use a pressure washer.

Do not use any acids, or acid-based solutions.

Do not use any kind of abrasives or scouring pads.

Do not use a sandblaster.

Do not use any metal tools or wire brushes.

Do not use bleach or any other form of household cleaner.

Even though we are dealing with stone, the rule is a simple one: always be as gentle as possible. Always use the least aggressive approach. The recommended cleaning agent is plenty of clean water. Clean water and elbow grease will accomplish wonders. Once you have determined that an ancestor’s gravestone can indeed be safely cleaned, assemble a cleaning kit. It is listed in the box accompanying this story.

Begin by thoroughly wetting the stone. The pump sprayer allows you to use less water, both while wetting and rinsing. Keep it wet while you are cleaning. If the stone has lichens, moss or algae on it, let it soak a bit, then wet it again before starting to scrub. If it has live ivy attached, do not attempt to remove it. It can tear away part of the stone. Clip the stem and leave the attached part to die, and come back another day. Once it is withered, the adhering fibers will easily break, and then you can soak it and scour away the remaining traces with a brush, or a plastic scraper.

When the stone is thoroughly wet, start scrubbing in a random orbit pattern. Clean the back of the stone first. Many people start with the front of the stone, and run out of energy before they get to the back. Work from the bottom to the top, rinsing frequently. Be sure to keep the stone completely wet as you work. Stubborn lichens may take more soaking and scrubbing. Whatever tools you use from your cleaning kit, be sure only to work on a very wet stone. When you are finished, rinse, and rinse again. The process requires time, patience, persistence and, above all, gentleness.

Remember, even though you might not see it, even the gentlest cleaning removes part of the surface of the stone. It is recommended that gravestones only be cleaned every five to seven years.

More information can be found online on the Oregon Heritage website at www.oregonheritage.org or www.gravestonestudies.org .

Michael Leamy operates Greenwood Cemetery, and serves on the Oregon Commission on Historic Cemeteries.