How to Clean a Headstone Safely: What to Use and What Will Ruin It

A headstone that has gone grey with lichen or black with grime looks neglected even when the family visits every month. Cleaning it is one of the most satisfying things you can do at a grave, and one of the easiest to get wrong. The stone has to last another hundred years; the cleaning should not take any of that away.

First, identify the stone

• Granite (most stones since about 1950): hard, polished, speckled grey, black, pink or red. The most forgiving to clean.
• Marble (common before 1950, and in most older cemeteries): white or grey, often sugary or pitted on the surface, lettering softened. Soft and easily damaged.
• Limestone and sandstone (older and rural stones): even softer than marble; flakes and crumbles when scrubbed.
• Bronze (flat markers, often on a granite base): a metal plaque that develops a brown or green patina.

If a stone is cracked, flaking, leaning or has lettering that is already faint, do not clean it at all. Cleaning a stone that is failing accelerates the failure. Photograph it and talk to the cemetery about conservation.

The safe method for granite and marble

1. Bring plenty of clean water. Two or three gallons. Most cemeteries have a spigot; do not count on it.
2. Wet the whole stone first. A dry stone absorbs dirty water into the pores. Soak it, then keep it wet throughout.
3. Use a soft natural-bristle or nylon brush. Never wire, never a scouring pad. A wooden or plastic scraper for thick lichen, held flat.
4. Scrub gently in small circles, bottom to top so dirty water does not streak dry stone below. Rinse constantly.
5. For biological growth (lichen, algae, black mold), use a cleaner made for stone monuments, the type used by cemetery conservators and sold under names like D/2. Apply, wait, scrub lightly, rinse. It keeps working for weeks after.
6. Rinse thoroughly and let it dry. Marble may look only slightly better on the day and much better a month later as the cleaner finishes its work.

What will ruin a headstone

• Bleach and household cleaners. Salts left in the stone draw moisture and spall the surface for years after.
• Pressure washers. Blast away the surface of marble and open the joints of granite.
• Wire brushes and abrasives. Scratch granite and destroy marble lettering.
• Shaving cream, flour or chalk to read lettering. They leave residue that feeds growth. Use a mirror to throw raking light across the inscription instead.
• Sealants and waxes. Trap moisture inside the stone.

Bronze markers

Wash with water and a soft brush. If the family wants the plaque bright rather than patinated, a light application of paste wax made for bronze, after cleaning, slows the darkening. Do not use metal polish; it removes the protective coating the foundry applied. Many cemeteries will refinish bronze markers for a fee.

When to call a professional

Stones that are leaning, sunk, cracked, or stained with rust or oil need a monument company or a cemetery conservator, and most cemeteries can recommend one. Resetting a leaning stone in particular is not a family job; stones are far heavier than they look and are the most common cause of cemetery injuries.