If you've spent any time in an old cemetery, you've probably wondered how to clean lichen off gravestones without causing permanent damage to the memorial. It's one of those things that starts small—just a tiny speck of gray or green—and before you know it, the entire inscription is buried under a crusty, stubborn layer of biological growth. Seeing a loved one's headstone looking neglected can be tough, but rushing in with the wrong tools can actually do more harm than the lichen itself.
Lichen is a fascinating organism, but it's a total nuisance for stone. It's basically a partnership between fungi and algae, and it loves to anchor itself into the tiny pores of granite, marble, and limestone. Over time, those little anchors (called rhizines) can expand and contract with the weather, slowly popping off tiny flakes of stone. If you want to keep that history intact, you've got to get rid of it the right way.
Before You Start: Check the Stone's Health
I can't stress this enough: don't just start scrubbing the second you arrive at the gravesite. The very first thing you need to do is a "health check" on the monument. If the stone is "sugaring"—which is a fancy way of saying it's crumbling into sand when you touch it—or if there are large cracks and delaminating layers, stop right there.
Cleaning a fragile stone can accelerate its decay. If the surface is flaking off, you might end up scrubbing away the name and dates along with the lichen. In those cases, it's better to leave it alone or call in a professional conservator. But, if the stone feels solid and isn't falling apart, you're usually good to go.
What to Avoid (The "Never" List)
Before we talk about what works, we have to talk about what will ruin a gravestone. A lot of people think that because a stone is well, stone, it's indestructible. That's a huge mistake.
First, never use bleach. It might make the stone look bright and white for a few weeks, but it's a disaster in the long run. Bleach contains salts that get trapped inside the stone's pores. When those salts crystallize, they expand and can literally blow the surface of the stone apart from the inside out.
Second, leave the pressure washer at home. The high-pressure stream can force water deep into the stone and blast away the finish. Lastly, stay away from wire brushes or metal scrapers. They leave behind bits of metal that rust, and they'll scratch the polish off granite faster than you can say "oops."
Gathering Your Supplies
To do this right, you don't need a lot of expensive equipment, but you do need the right stuff. Here's what I usually pack in my cleaning kit:
- Lots of water: I'm talking gallons. If there isn't a spigot nearby, bring your own jugs.
- Plastic scrapers: Think of those little plastic spatulas used for scraping dough or even an old credit card (though a dedicated plastic putty knife is better).
- Soft-bristled brushes: Natural fiber brushes or soft nylon brushes are perfect. Avoid anything with stiff, hard bristles.
- A biological cleaner: This is the secret sauce. Products like D/2 Biological Solution or Orvus Paste are the gold standard. They aren't acidic and they don't contain harsh salts.
- A spray bottle: For applying your cleaner evenly.
- Wooden skewers or toothbrushes: These are great for getting lichen out of the deep grooves of the lettering.
The Step-by-Step Cleaning Process
Once you've got your gear and you've confirmed the stone is stable, it's time to get to work. Here is the most effective method for how to clean lichen off gravestones while keeping the stone safe.
1. The Pre-Soak
Water is your best friend. Before you touch a brush to the stone, soak the entire thing with clean water. Lichen is like a sponge; when it's dry, it's hard and brittle, which makes it grip the stone tighter. When it's wet, it softens up and becomes much easier to move. Give it a good five to ten minutes of soaking before you start.
2. Gentle Scraping
Take your plastic scraper and gently—seriously, be gentle—start to flick away the larger clumps of lichen. You aren't trying to gouge it out; you're just trying to remove the bulk of the growth. If a piece doesn't want to come off, don't force it. Just move on to another spot. You'll be surprised how much comes off just with a bit of water and a plastic edge.
3. Apply the Biological Cleaner
Spray your biological cleaner over the entire stone. If you're using something like D/2, you can let it sit for about 10 to 15 minutes. These cleaners work by soaking into the lichen and killing the organisms at the root level. The best part is that they keep working long after you've left the cemetery.
4. Scrubbing in Circles
Using your soft-bristled brush, start scrubbing the stone. It's best to work from the bottom up. Why? Because if you start at the top, the dirty water will run down the dry stone and potentially leave "clean streaks" that are hard to get rid of later. Use a circular motion and keep the stone wet at all times. If it starts to dry out, spray more water or cleaner.
5. Detailing the Letters
This is where the toothbrushes or wooden skewers come in handy. Lichen loves to hide inside the "O's" and "R's" of the person's name. Carefully pick out the growth from these areas. This is usually the most satisfying part of the job because you can finally see the details emerging again.
6. The Final Rinse
Rinse the stone thoroughly with clean water. You want to make sure all the loosened gunk and suds are washed away. Take a look at your work—it might not look perfect yet, and that's okay.
The Virtue of Patience
One thing people often don't realize about how to clean lichen off gravestones is that the results aren't always instant. When you use a biological cleaner, it stays in the stone. Over the next few weeks and months, the rain will continue to wash away the dead lichen roots.
Sometimes, a stone will actually look a bit "off" right after cleaning—it might turn a slight orange or gray color as the lichen dies. Don't panic. Give it a month or two, and you'll likely see a massive improvement as the stone's natural color returns. In some cases, for very heavy growth, you might need to come back for a second round a few months later.
Keeping it Clean
Once you've done the hard work of removing the heavy lichen, maintenance is pretty easy. Usually, a quick scrub with plain water and a soft brush once a year is enough to keep the lichen from taking hold again. If you keep the stone clear of grass clippings and fallen leaves, you're also cutting off the "food" that lichen and moss love.
Cleaning a gravestone is a labor of love. It's a way to show respect for the people who came before us and to ensure their names aren't forgotten under a layer of green crust. Just remember to take your time, use the right materials, and always prioritize the preservation of the stone over making it look "brand new." Old stones have character, and our job is just to let that character shine through again.