Cleaning Cemetery Monuments:

Get permission. Contrary to popular opinion, not everyone wants gravestones to be cleaned. Whenever possible, contact the family/descendants of the deceased before you clean a gravestone. In most cases cemeteries do not own the markers, so attempting to locate family is recommended even if the cemetery owner/association gives permission.

How's the weather? The primary ingredient of ANY cleaning project is water. Therefore, do not attempt to clean gravestones on hot sunny days. Fall and Spring are by far the best times of the year for gravestone cleaning, because the biological growth will be soft and easily removed, the stone will not dry out and stain while you are working, and you'll stay cooler and more comfortable as you work. Rainy days are good for cleaning, but heavy downpours can wash away your cleaning solutions. Never clean (or be outside) during a thunderstorm.

What do you hope to accomplish? When you undertake a cemetery cleaning project you must first determine what you want in the way of "clean". Remember that old, weathered stones do not have to look new. Some old grave markers are just too far gone or too delicate to clean under any circumstances. There are various grades of marble, and poor grades may have a "melted" look as minerals have been washed away by rain. Others will feel "sugary" when you run your hand over them indicating that the structure of the stone has deteriorated. Still, others will have noticeable cracks or amateur repairs that could be easily expanded or break with the slightest pressure from a scrub brush. Avoid cleaning any of these stones. A stone that can be cleaned with relative safety is one that is sturdy and solid, has no noticeable surface deterioration, and has no (or only minor) surface cracks.

Avoid Harsh Cleaning Materials/Techniques. Approach each project, no matter what material the grave marker is made of, by asking yourself, "what is the gentlest means possible? The quickest or cheapest method is not necessarily the gentlest. Make test patches of your proposed cleaning technique on an area of the structure that is least visible. Begin with plain water (at garden hose pressure) and a soft bristle brush. You will find that some foreign materials are removed quite satisfactorily with this simple approach.

Never use wire brushes on headstones or other monuments. "Do you clean your teeth with a wire brush? No!" Wire brushes, metal instruments, and abrasive pads may give you instant satisfaction but, if you clean with anything that is harder than the stone, you risk scratching the face of the stone and causing more damage in the long run.

Powerwashers are also NOT recommended. Anything that puts out greater than 60 psi is too much force to use on older fragile stones. A garden hose putting out a gentle soaking spray is enough to clean and flush the stone (garden-type sprayers also work well).

Consider the Stone Type. For marble, limestone, and sandstone, use water and soft bristle brushes, natural or nylon. If you are in doubt about whether the bristles of your brush are soft enough, decide if you would use them to wash the paint on your car; if they would scratch your car paint, they are too stiff for marble gravestones. Granted it doesn't sound like a miracle cleaner and it doesn't happen quickly but with some patience and time, this will clean most environmental soiling and lichens from stones. Keep the stone wet at all times; really wet. Where a garden hose is not available, be sure to bring plenty of jugs of water and keep dowsing the stone as you work. If you are working on a large or multiple-sided monument, clean one side at a time, and scrub the stone from the bottom up to avoid streaking and further staining. Most importantly, flush the stone well when done.

Biological Growth Requires Special Attention. If the gravestone is heavily covered with moss or lichen, there is only one safe method for removing it. Do not try to remove dried-on biological growth, and do not apply any chemicals or gardening products as they will cause serious damage. Clean biological growth during the rainy season, on a rainy day. If your timing is right, with a gloved hand, soft wet cloth, or wooden spoon you will be able to gently wipe away the water-saturated moss and/or lichen. If necessary, remove the growth from the carving with a soft-bristled brush or toothbrush. Wipe the surface with a wet cloth and thoroughly rinse the stone with water. During dryer seasons, take plenty of water with you on the day of your cleaning project, and proceed with the above method.

Avoid Harmful Chemicals. Stones are composed of minerals and salts. Adding chemicals to them can often cause chemical reactions that will erode the stone faster than if you just left it alone. Some seemingly helpful household cleaning agents can be just as harmful to monuments as wire brushes and power washers. This damage is not immediately evident, as in the case of using bleach on marble. Household bleach is sodium hypochlorite. While fine for killing germs in the bathrooms and kitchens of your homes, sodium is most destructive to marble gravestones. Marble gravestones are calcium carbonate, and the sodium in the bleach reacts chemically with the calcium in the stone to form a salt -- eating away calcium from the gravestone. Unfortunately, the damage is not immediately apparent, so household bleach is frequently recommended by well-meaning folks, as a quick and effective cleaning method. Afterward, during every rainfall or lawn watering, particles of the gravestone are simply washed away. When this process is used on particularly soft marble and limestone, the lettering is the first to disappear. Something that is over 100 years old shouldn't look bright and new!

If one is insistent upon bleaching a discolored stone, there is a type of bleach that does not contain sodium. Calcium hypochlorite or HCL is available at home improvement and hardware stores; it is generally sold as a swimming pool disinfectant or chlorinator. The calcium in this bleach does not react chemically with the calcium carbonate of the gravestone and can be safely applied to the surface. Read the package ingredients list carefully when buying these products, because some of them do contain harmful sodium hypochlorite. Look for the words calcium hypochlorite or HCL on the label. HCL is generally sold in crystalline form, and it is important to note that warm water is required to dissolve the crystals. Do not add any other cleaning products to this solution. Follow the same cleaning techniques when applying the HCL as you did when cleaning with pure water… begin at the bottom, scrub gently, keep the surface wet, and use progressively smaller brushes. Be aware that some stains quickly disappear while others fade more slowly. Many stains will become lighter once the stone has completely dried, so do not be concerned if there are some traces remaining after your cleaning. Remember to thoroughly rinse the stone when you have finished cleaning.