The Proper Way to Clean a Headstone
Compiled by: Dusty Smith-Bearden
It is recommended that clean clear natural spring water only be used for cleaning historical cemetery structures. Do NOT use harsh chemicals, high pressure hoses or equipment, or abrasive tools of any kind.
Historical Stone Cleaning Procedures
1. Do not clean a headstone or monument if the stability of stone is questionable. This includes but is not limited to:
a. Flaking on or around the face or lettering.
b. Significant fractures anywhere on the headstone or monument.
c. Any grainy surface that readily falls away, such as limestone, concrete or coquina, should not be cleaned.
d. Any condition that indicates that the headstone is delicate, brittle, or otherwise in a vulnerable state.
e. Never clean a wooden headstone. Even if the marker looks stable, you can’t tell if it is weather damaged on the inside of the marker or at its base in the ground.
f. Cast iron headstones should be cleaned in the same manner as granite or marble headstones. Do not try to remove rust or flaking metal as it will harm the inscriptions, symbols and icons on the headstone or monument.
g. White Bronze (zinc) headstones and monuments were meant to “weather” so the ionization of the metal would continue to build in the welds and make for a sturdier hold on all joints.
2. Do not clean marble, sandstone, or slate stones too frequently; once every ten years are sufficient.
3. It is not necessary to clean a headstone simply due to naturally occurring fungi, algae, and/or lichens. Cleaning these naturally occurring floras may do more harm than good to the headstone.
4. Use soft-bristled brushes with natural or plastic bristles. Never use a wire brush or any metal object for cleaning. Automobile detailing brushes are very handy for cleaning historic headstones and monuments. (Thank you Michele for this helpful tip)
5. Remove loose dry materials with a soft-bristled brush.
6. Use lots of natural clear water. Water from a well or tap that contain high levels of additives of natural sulfurs and other minerals are not recommended. If hard water is the only type of water available, you may want to wait until you can purchase some bottles of all natural spring water.
7. When in doubt, use MORE natural clear water.
8. NEVER use a sandblaster or pressure-washer on any headstone or monument.
9. Do not use water pressurized more than 30 pounds per square inch on marble, sandstone, or slate stones. Do not use more than 65 pounds per square inch on granite. If at all possible, NEVER use pressurized water to clean a headstone or monument. This includes water coming directly from a hose. A small pump up garden sprayer is a good tool for cleaning headstones and monuments. Never ever sandblast or pressure-wash a limestone headstone if you want the stone surface to remain in tact. If other dirt and discoloring remains after using a weak diluted bleach solution, try using a neutral ph soap with a soft bristle brush.
10. Clean all headstones and monuments from the bottom up to avoid streaking.
11. Do not use cleaning solutions unless absolutely necessary and then use a lot of water quickly to remove the cleaning solutions.
12. Follow instructions and precautions on cleaning solution labels. Avoid inhaling, ingesting, and or contact with skin. If a cleaning solution can harm you, it can harm a historic headstone, so it’s best to use clear water.
13. Always work upwind during cleaning operations.
14. Use personal protective equipment such as chemical-aprons and shoes; and goggles or face shields as recommended.
15. If cleaning solutions are necessary to use they should always be:
a. They should always be biodegradable.
b. They should be non-ionic, non corrosive and non flammable.
c. Never use cleaning agents that are abrasive in any way.
d. They should always be colorless and odorless.
e. They should be hard water tolerant.
f. They should always be non-staining.
g. At one time it was recommended to use shaving cream as a cleaning agent on headstones and monuments. This came about when cemetery photography became more popular and inscriptions couldn’t be read well. Do NOT use shaving cream to clean headstones or monuments. It has now been found to damage the stone because of the often high levels of alcohol and menthol in the shaving cream.
h. Sand should also not be used as a cleaning agent. It can scratch the surface of granite, marble, limestone, sandstone and other materials.
16. Household ammonia can be used to clean headstones and monuments if it is absolutely necessary. The ratio is one cup of ammonia to one gallon of water. However, ammonia is often not effective as a cleaning agent.
17. Chlorine bleach is never recommended for cleaning headstones and monuments. However, if chlorine bleach must be used, use a very weak solution. It should never be stronger than 30/70+. Thirty percent chlorine bleach with seventy percent or more water. Rinse immediately with lots of natural clear water. And you can use vinegar at any time during the cleaning process to neutralize the chlorine bleach. Household bleaches often contain sulphates that may cause exfoliation of the surface of the headstone or monument and as these salts dry out and re-crystallize in the pores on the surface of the structure. Bleaches can also produce light brown staining after a period of time.
18. Do not use any solution which has not been specifically approved for cleaning historically sensitive stones.
19. After using each individual cleaning agent, rinse it away thoroughly with lots of natural clear water. NEVER allow cleaning solutions to dry or stand on a headstone or monument, this will only damage the stone and defeat your purpose.
20. Do not attempt to remove deep-set stains which remain after cleaning.
21. Do not use protective coatings that are impermeable to water vapor. This process will either stain or damage the stone and cannot be undone.
22. Do not repeat cleaning of any headstone of monument for at least 10 years.
23. Report any damage, not matter how slight or severe, immediately to the caretaker or owner of the cemetery. This will aid in lessening more potential damage to the headstone or monument.