How to clean a headstone without harming it

Cleaning a family member’s headstone is a quiet, caring thing to do, and it’s worth doing slowly and gently. Old stone is more fragile than it looks, and a lot of the advice floating around — bleach, a stiff wire brush, a pressure washer — will brighten a stone today and quietly damage it for good. This guide walks through the careful way, drawn from the people who care for military and historic markers for a living. There’s no rush here. A headstone that has stood for a hundred years can wait for a still afternoon and a soft brush.

Two things before you start, both from federal cemetery guidance: only clean when it’s above about 40°F, and get permission from whoever owns or manages the cemetery before you clean a stone that isn’t on your own land. Many cemeteries and districts have their own rules, and a quick ask is the respectful first step.

First, decide whether to clean at all

Not every stone should be cleaned. A soft, sugaring, flaking, or cracked stone — one that sheds grains when you brush it, or where the surface is coming away — is too fragile, and cleaning can take the carved detail with it. If the stone is unstable, leaning, or actively crumbling, the kind thing is to leave it and, for a historic marker, ask a conservator. When in doubt, do less. A little lichen on a sound stone is not an emergency.

What you’ll need

The whole point is gentleness. Gather:

• Plenty of clean water — this is the main tool, and the stone should stay wet the entire time.
• Soft natural or nylon bristle brushes. The VA is explicit about this: no metal and no plastic bristles. A range of sizes helps for lettering and carving. A wooden or plastic scraper (never metal) for stubborn spots.
• A pump or spray bottle, or a bucket — anything that keeps the surface wet. Not a power washer.
• Optional: a gentle biological cleaner such as D/2 Biological Solution for algae, moss, and dark biological growth, if plain water and patience aren’t enough. More on that below.

The gentle method, step by step

Federal cemetery guidance lays out a simple, low-risk sequence:

1. Soak the stone with water first. Wet it thoroughly before anything else, and keep it wet throughout — a dry stone lets a cleaner concentrate and can streak or etch.
2. Work in small areas, from the bottom up. Starting low and moving upward prevents the dark streaks that run down a dry lower section when you start at the top.
3. Brush gently in soft circular motions. Let the water and, if used, the cleaner do the work over time. This is loosening biological growth, not scrubbing off paint. If it’s not coming off with gentle effort, give it more dwell time rather than more force.
4. Rinse thoroughly, especially if you used any cleaning solution, so nothing is left behind on the surface.

That’s genuinely it. Water, a soft brush, patience, and a light hand.

About D/2 and biological growth

For green algae, moss, and the dark biological staining that builds up on shaded stones, plain water may not be enough, and this is where a biological cleaner earns its place. D/2 Biological Solution is the product most often recommended by preservation professionals: a National Park Service study conducted with the National Center for Preservation Technology and Training (NCPTT) evaluated commercial cleaners on marble headstones and found D/2 among the best performers, and the VA lists it among acceptable biological cleaners for government markers. Used as directed — the stone kept wet, a soft brush, a rinse — it works slowly and keeps working for weeks after you leave, so the stone often looks better a month later than the day you cleaned it.

Follow the manufacturer’s directions for dilution and dwell time, and don’t reach for something harsher because it’s faster. It isn’t worth it. If you’d like the longer story — what D/2 actually is, why the federal studies landed on it, and what it won’t do — we’ve written a full D/2 Biological Solution explainer.

What damages stone — please don’t

This is the part that matters most, and it’s the part the internet gets wrong. The federal sources are blunt about what to keep away from old stone:

• No bleach or products containing sodium hypochlorite, and no other household cleaners. The NPS study found that bleach-type products leave soluble salts in the stone that cause surface loss and powdering of marble over time — a slow ruin that shows up years later.
• No strong acids (hydrochloric / muriatic) and no strong bases (concentrated ammonia). These etch and dissolve the surface.
• No wire brushes and no metal tools. They scratch stone and leave iron behind that rust-stains it.
• No pressure washing. The VA prohibits the public from power-washing its markers precisely because of the damage it causes; the force drives water into the stone and blasts away softened surface and detail.

If you take one thing from this page: the shine you’d get from bleach or a pressure washer isn’t cleaning — it’s the stone slowly giving up its surface. Water and a soft brush protect the very thing you’re trying to honor.

A quiet note for cemetery districts

If you help run a small cemetery district, you already know that caring for the stones is only half of it — the other half is the records behind them: who’s buried where, who holds which plot, the deeds and the plat that only one person may still know how to read. That’s the part we help with. CemeteryClerk keeps a district’s plot, owner, and burial records in one place the whole board can find, so the knowledge doesn’t retire when the clerk does. If that’s a worry where you are, there’s a note below — no pressure, just here when you need it.