Being able to recognize any damage to a gravestone before cleaning it can help prevent more damage from happening and knowing what cleaning methods and materials to use will help in preserving the gravestone.
What are Gravestones made from?
Gravestones are made from some of the finest natural materials on earth. Many of these natural materials are created into beautiful pieces of art by skilled craftsmen.Over the centuries a variety of materials have been used for creating gravestones. The type of material used depended on the era, and what materials were available in the area. Some of the materials used were: marble, granite, sandstone, limestone, bronze and wood.
Different types of gravestones will require different cleaning methods. Marble and Limestone need to be treated more gently than granite. Where granite can be cleaned every 2-3 years, marble, sandstone, or slate stones should be cleaned no more than 8-10 years.
Wooden headstones should only be cleaned by an expert. Even if the marker looks stable, you can’t tell if it is weather damaged on the inside or at its base in the ground.
Cast iron headstones should be cleaned in the same manner as granite gravestones. Do not try to remove rust or flaking metal as it could harm the inscriptions, symbols and icons on the gravestone.
White Bronze (zinc) gravestones were meant to “weather” so the ionization of the metal should continue to build in the welds and make for a sturdier hold on all joints.
How to Check for Damage and Cleaning Needs:
Because gravestones are exposed to airborne pollution, such as acid rain, chemical residues from fertilizers, severe weather conditions and mineral deposits from water some maintenance is usually needed.
Gravestones that are in direct contact with the earth are constantly drawing water from the ground and then evaporating it along its surface. This water may have dissolved salts, minerals such as iron and copper and other pollutants.
You should first determine whether or not the stone actually needs cleaning. Many people think that signs of aging are dirt or grime. Marble and other materials do naturally fade over time.
Examine the gravestone for any flaking, scaling, cracks, or eroding granular surface. If you see these signs of damage, you may want to consult with a professional before cleaning. Use extreme caution if you decide to proceed. Cracks are an obvious sign of damage. Any damage can be an indication that the stone is weakened. Avoid putting pressure on the weakened areas. It is better to leave some dirt than to put additional stress on the stone. If there is soiling present, determine the type. Types of soiling could be carbonaceous or sooty soiling, urban grime, dirt, organic-algae, fungi, lichens, mosses, stains-metallic, oils. or efflorescence–salts.
Again, if there is any damage or weakened areas on the stone you may still want to consult with a professional.
Lichens and Fungi:
Lichens is the most common to see on a gravestone. Lichens are living organisms that are similar to a fungus. They come in many different colors, such as grey, green and yellow. Lichens can harm gravestones by trapping dirt, organic debris and moisture on the surface of the gravestone. Because gravestones are somewhat porous, the lichens also can trap these contaminants under the surface of the stone. Moss and other molds can also be present, which are usually caused from weather conditions.
What Tools Are Needed?
Here is a list of suggested tools that are best to use when cleaning gravestones. When using a scraping device it is important that it is softer than the stone. Hard objects damage the outer layers of the gravestone, making it more susceptible to the elements.
Sprayer bottle – Use for wetting down the stone or spot cleaning
Clippers – Use to clean away any grass or weeds.
Bucket With Lid – To store your supplies and used as a seat.
Rubber Gloves – Protect your hands cleaning products.
Nylon Brushes – Use only soft natural or white bristled.
Plastic Scraper –Only use plastic or wood.
Q-tips – Used to get into small cracks.
Sponges – Soft sponges.
Tooth Brushes –To get in small spaces.
Water – Wetting, cleaning with and rinsing
Whisk Broom – To sweep off the stone before cleaning.
Paint Brushes – soft for cleaning engraving, etc
Towels or old T-shirts
Protective Eye ware – Especially if using cleaners or scraping debris
Cleaning Solutions – What Not to Use or Do:
There are many detergents, cleaners that should not be used to clean gravestones, along with tools that can cause damage.
Chlorine bleach should never be used for cleaning gravestones or monuments. Household bleaches often contain sulfates that may cause exfoliation of the surface of the gravestone and as these salts dry out and re-crystallize in the pores on the surface. Bleaches can also produce light brown staining after a period of time.
Hydrochloric acid can cause rust staining and the deposition of soluble salts.
Sodium Hydroxide mixed with water forms a caustic soda and can cause the formation and deposition of soluble salts and rust staining.
Fantastic contains 2-butoxyethanol (butyl cello solve), alkaline builders, water, fragrance, and dye. It is not recommended for cleaning any porous or polished surfaces.
Formula 409 contains ethylene glycol, even though a non-ionic detergent, alkaline builders, water fragrance and dye and is not recommended for masonry or polished surfaces.
Spic-n-Span is an abrasive cleaner containing sodium chloride, sodium sulfate, sodium carbonate, sodium bicarbonate and ammonium carbonate. It will form and deposit soluble salts.
Marble and limestone, for example, are easily dissolved by acidic cleaners, even in diluted forms. Chemicals can react with components in mortar, stone, metals, wood or brick. They can create soluble salts, which can cause a buildup of these salts beneath the surface of the stone eventually causing spalling.
Do not assume that the label of contents is a complete list of all the chemicals contained in a household detergent product.
Tools To Never Use:
Never use metal brushes, metal scrapers, metallic scrubbers or abrasive pads of any type, including, “Brillo” and “Scotchbrite.” Never use a sandblaster or pressure-washer on any gravestone or monument. Never use pressurized water to clean a gravestone or monument. This includes water coming directly from a hose that is under pressure.
What Cleaners Should You Use Use?
Time and weather can cause a gravestone to look less than pristine. Once you have accessed that your gravestone is dirty and in need of cleaning you will may need to choose a cleaning product. The following is a list of several acceptable cleaners. You may find that water and some gentle scrubbing is all you need and not have use a cleaner at all.
Detergents Non-ionic (e.g., Photo Flo – a Kodak Product, or Trion-X 100) are recommended for cleaning gravestones. They are electrically neutral cleaning agents that do not contain or contribute to the formation of soluble salts. Non-ionic detergents are available from conservation, janitorial, and photographic suppliers. A suggested cleaning solution is one-ounce of non-ionic detergent to 5 gallons of water. Always read the label carefully to ensure that it says “non-ionic”.
Acetic acid (e.g. vinegar) is less aggressive than other acids, solutions have been recommended for the removal of general soiling from limestone. Oxalic acid is not recommended for general cleaning, but is recommended for rust staining removal on light-colored granites, one pound to one gallon of water.
Calcium Hypochlorite (e.g. Chlorine) is effective for the removal of biological growth; mix one ounce to one gallon warm water. Available from swimming pool suppliers. Requires a lot of thorough rinsing with water and Hydrion Paper test strips for pH testing.
Ammonium Hydroxide (e.g. household ammonia) diluted 1:4. is recommended for cleaning light colored stones and is particularly effective for the removal of biological growth. Requires a lot of thorough rinsing with water and Hydrion Paper test strips for pH testing.
Quaternary Ammoniums (e.g. algaecides) are especially effective for the removal of stubborn black algae and biological growth. Also available from swimming pool suppliers.
Before you start, be aware if there is a frost or freeze warning. It will take a period of days, perhaps weeks, for the water to evaporate from the pores of the stone, and surrounding area. Also if it is a hot sunny day, be sure that you constantly keep rinsing the stone so that the cleaner you are using doesn’t not dry on the stone.
How Do You Clean?
You should use some personal protective equipment such as aprons, rubber gloves, shoes; and goggles or face shields, especially if you are using cleaners.
Once you have checked the stone over closely and determined that it is not damaged, and safe to proceed then you are ready to begin the cleaning process. If you are using a cleaner, follow the directions on the label and be sure that it is well mixed with the proper ratio of water.
Start by pre-wetting the stone with water. Pre-wetting prevents excessive penetration of cleaning solutions into the stone and facilitates softening of soiling such as lichens or moss. Wet your sponges in your bucket of water and gently begin wiping down the surface of the stone.
Remove any growth and build up lichens or moss by using plastic scrapers that are soft and flexible and can get the job done without damaging the gravestone.
After you have removed the first layer of dirt or grime, you can use your brushes. Wet the brushes, then use them by gently scrubbing in a circular motion over each part of the stone. It is best to start at the bottom of the stone and work your way up. This will help you to avoid leaving streaks. Keep the brush wet by dipping it into a bucket of clean water or running water from the hose over the bristles. When cleaning carvings and lettering, use a soft bristled toothbrush.
If you feel that water alone is not accomplishing the results you would like, move on to whatever cleaning product you have decide to use. Again remember to clean from bottom to top of stone to avoid streak staining the stone and frequently rinse off the stone with water. (You may want to test your selected cleaner before a general application. Test in a small inconspicuous area and evaluate the results when dry.)
If lichens or moss is a problem, after scrapping you can use an ammonia mixture. Combine one-part ammonia with four parts water. Using a clean sponge, gently scrub the affected area with the ammonia mixture. After you are done, rinse with plain water.
For a more natural method, people have used snails to clean their stones. Snails consume many of the materials that grow on gravestones, such as lichens, mold, and fungus.
After cleaning and rinsing the entire gravestone, wipe it with paper towels or soft cloths to prevent the stone from streaking as it dries. Residues from cleaning solutions can create a blotchy appearance, provide a medium for bacterial action, and cause staining. Do not allow cleaning solutions to dry on a gravestone.
Keep a Record:
Gravestones do not require regular cleaning. Although it might seem natural to want to frequently clean them. You should clean the stone approximately 2-3 years unless it is marble, sandstone or limestone, which should only be cleaned every 8-10 years. Write down the date each time you clean the stone. This will help prevent you from over cleaning.
If the whole process sounds too difficult for you to do, you can talk to the cemetery caretakers and see if they provide any service maintenance plans or if they know of someone that provides professional cleaning service.
When Should You Consult an Expert?
If you have any concerns about the condition of the gravestone, it is a good idea to talk to an expert. For example, an expert will be able to tell you the approximate age of your stone. They will also be able to identify the material of the stone, and be able to inspect it for damage. Contact the cemetery to ask if they can recommend someone you can consult with.
I hope you found this information helpful. If you have any questions, please feel free to contact me.