When people think of preservation they naturally think of preservation of artifacts, buildings or battlefields. Cemeteries never come to mind. However, there is a small group of people that are very active in this field.
When I am contacted about cemeteries, by far the single most frequently asked question is "How do I clean headstones?" It's also the most controversial and complicated of them all.
Start by considering the difference between preservation and restoration. In preservation you clean the cemetery; in restoration you clean the marker.
With abandoned or neglected sites you have your work cut out for you. The highest priority is to document everything through maps, such as how to get there, and the site itself. GPS and photograph every conceivable item from depressions to monuments to fence lines.
In order to find all attributes of the site it should be cleared of all opportunistic plants, taking care not to remove family plantings. Opportunistic trees grow where they want to and can engulf or encase small markers.
Tall bushes can cause tipping and knock markers over from root systems. These should all be removed. Large strategically planted trees should be thinned out and all deadfall or poorly growing branches removed. You might wish to consult an arborist.
Here is where the payoff comes in. Markers are preserved and protected from falling trees and branches. You also brighten up the area, subsequently drying the ground a bit due to increased sunlight.
Molds that come in black, gray, orange and several other colors; lichen, which are actually plants with flowers; and fungus that grow on markers will start to die off in dryer, brighter conditions.
You have now cleaned your marker a little bit without even touching it and with no risk of damaging it.
In more formal sites it's usually as simple as trimming a bush or pulling a few weeds. Ground cover should be grass which keeps dirt from splashing up during rains. Pick up rocks that might be thrown by lawn mowers and chip or scratch any marker.
Restoration is to clean the stone. Stones are composed of minerals and salts. By adding bleach, acids, acetone or other strong chemicals you start a chemical reaction that will erode the stone at a greatly accelerated rate.
This damage may not be immediately evident. These chemicals will give you an instant brightness, but if these chemicals remain on the stone it will actually stain the stone brown just from the chemicals. Strong chemicals will strip the patina, vintage look or the historical look off, robbing a stone of its history at the least.
Ruth Brown from the Connecticut Gravestone Network puts it this way: "Enough with the wire brushes and strong chemicals! Would you clean your teeth with a wire brush and bleach?"
I'm just as conservative so I will approach cleaning in an incremental fashion - cheap and safe to advanced and dangerous then to never allowed.
For any and all chemical agents, start with one tablespoon per gallon of water, wash then rinse. Then rinse again. If the desired effect is not achieved, then add a few more tablespoons until you get the effect you desire. Always rinse well when done, then rinse again.
The safest seems to be D/2 antimicrobial soap but it's expensive. Architectural preservationists use it in large quantities to clean buildings.
Photo-Flo is a soap used in processing photographs and has a neutral pH (measure of acidity or alkalinity). It can be purchased from a photo supplier. This requires an extra trip and the ability to store it between uses along with an extra cost.
Liquid Ivory or Dove soap contains no perfumes or preservatives. They also have no emulsifiers or chemicals to evaporate them quickly. They are cost-effective and most everyone has some around or can get it from any or grocery store. The leftover can be used around the house.
Bleach is sodium hypochlorite and contains salts that damage stone. After "cleaning" marble, careful inspection will reveal erosion and yellowing. Sugaring will happen naturally to very old marble or poor grades of marble. Bleach will cause sugaring and yellowing on any marble, new, old or poor grades.
When you rub your hand on the stone, you can look at your palm and see speckles or flakes that look like sugar. Only if you feel you must use bleach, litmus paper must be used to check the pH of the stone when done.
Experts say it should never be used, so do I. I have seen too many problems caused from bleach.
Ammonia, acids, acetone and wire brushes are all things that should never be used under any condition.
Pressure cleaners - shoot the operator then let God ask the questions. Sand, water, steel or glass shot, even pecan shells, it doesn't matter what you use. They have absolutely no place in a cemetery.
Yes, I'm getting repetitive to some of you, but I can't say it enough. You should shoot them on site and don't bother asking questions later.
Do It Right
The rule is when you start to clean any stone, start with a small spot on the back, clean it and then walk away for a while to let it dry. If no problems occur and your desired effect is achieved, then proceed.
Cleaning should be done from bottom to top, washing any grit and biogen (biological growth) away as you go. If I have a handy water source, you're in luck. I gently run water on the top and clean the back, sides then the front from bottom to top.
As I don't use chemicals, have too many stones to do and not enough time to do them, I can do three times more than anyone else with no damage using just water. If you use any chemical, remember to start with a diluted wash first.
The preferred method is just plain water and lots of it. If the biogen is stubborn then super saturate it with a towel wrapped around the stone, wetting is constantly for 30 to 40 minutes.
A natural pile brush and elbow grease are the best. Don't use stiff plastic bristles and never use a wire brush. Tong blades or Popsicle sticks work well for scraping lichen.
Just a last thought - don't lean on the stone or sit on it when you need more leverage to scrub it. Be gentle.
Mike Mitchell is a Paramedic in Miami, Fla. He is a longtime member of the Association for Gravestone Studies and the Chairman of the Graves and Monuments Committee for the Sons of Confederate Veterans.