My Honest D/2 Biological Solution Review After Two Years and Forty Stones

headstone cleaning in California | headstone cleaning in Los Angeles California

I still remember my first headstone cleaning. It was a little marble marker for a woman named Edna, tucked under a big oak tree in the old section of St. Mary's Cemetary. I had watched a YouTube video, bought a cheap spray bottle, and mixed up what I thought was a safe homemade cleaner. Big mistake. I scrubbed too hard with a stiff brush, and I left little scratch marks all over the face. Edna's family probably never noticed, but I did. I felt terrible. That night I called my nephew, who's a chemist, and he set me straight. He said, 'Aunt Margaret, stop guessing. Use D/2.' I ordered a gallon the next day.

Now, two years and about forty stones later, I feel qualified to give you a real D/2 biological solution review. Not from a lab or a marketing brochure, but from my own two hands, kneeling on the damp grass, wiping away dirt and lichen. I've used it on marble, granite, even a few old sandstone markers that were crumbling. I've made mistakes along the way, and I'll tell you about them. But if you're thinking about cleaning a family headstone, you need to hear what works and what doesn't. So here goes.

What D/2 Actually Is (And Why It's Not Like Bleach)

D/2 Biological Solution is a liquid cleaner that uses living bacteria and enzymes to eat the organic gunk off stone. That's right — it's alive. Not in a creepy way, but in a 'let nature clean nature' way. It breaks down moss, lichen, algae, bird droppings, and that dark grey grime that makes an old headstone look like it's wearing a dirty coat. It's pH-neutral, so it won't eat away at the stone itself. That's the whole point.

Compare that to bleach or other harsh household chemicals. Those kill the organic growth on the surface, sure, but they also soak into the stone and can cause salt crystals to form inside, which flake off the surface later. I've seen it happen on a limestone marker my friend Joan tried to clean with a pool cleaner. The stone looked good for a month, then started peeling like a sunburn. Never again. D/2 doesn't do that. It's gentle, it's slow, and it works because it's alive. You just have to be patient.

How I Use It: My Step-by-Step Routine (Not Fancy, But It Works)

I'm not a professional. I'm a retired teacher who carries a bucket, a spray bottle, and a soft-bristle brush in the trunk of my old Honda. Here's my routine:

First, I wet the stone with plain water from a spray bottle. This helps the D/2 spread evenly. Then I spray D/2 directly onto the stone — I don't dilute it. The label says you can dilute it for light cleaning, but for old crusty growth I use it full strength. I let it sit for at least 10 minutes. Sometimes I come back after 20 if the stone is really grimy.

Then I gently scrub with a soft brush. I use a nylon brush with bristles about an inch long. Not a wire brush — those scratch marble and sandstone like you wouldn't beleive. I scrub in circles, not back and forth, because I read somewhere that circles are less likely to leave lines. Probably true.

Then I rinse with clean water. I pour a bucket of water gently over the stone — no pressure washer. Pressure washers can blast the surface off old stone, especially sandstone. I learned that the hard way on a small test patch. The stone looked clean, but it felt rough, like sandpaper. I stopped immediately. Now it's just bucket water, gravity, and patience.

After rinsing, I let the stone dry completely. Then I look at it. Sometimes the lichen is gone but there's a dark stain left. That's okay — I spray D/2 again, wait, and scrub again. Some stains take three or four treatments. Took me three tries on a big granite obelisk. Worth it.

What D/2 Won't Do (And Why That's Actually a Good Thing)

D/2 is not a miracle worker. It won't remove paint, rust stains, or black soot from old coal fires. It won't fill in cracks or fix a broken stone. And it definately won't whiten the stone like bleach does. That's the thing — some people see the bright white result of bleach and think that's what clean looks like. But bleach is damaging. D/2 leaves the stone it's natural color. Sometimes that's a bit grey or tan, not blinding white. And that's okay. Clean doesn't mean bleached.

I had a woman once ask me why her grandfather's granite stone looked 'dull' after I cleaned it with D/2. I told her, 'That's the color of the rock. The dirt is gone.' She wasn't happy. But I'd rather have an honest clean than a damaged stone that looks like a bathroom tile. D/2 is for preservation, not cosmetics. If you want a stone that glows like new, you need a professional conservator, not a spray bottle.

My Honest Pros and Cons After Two Years

Let me be blunt. D/2 is not perfect. Here's my list:

Pros:

• Safe for almost all stone types. I've used it on marble, granite, limestone, and sandstone without issues.
• No harsh smell. It smells like damp earth, not chemicals. I can work without holding my breath.
• It keeps working after you spray it. The bacteria keep eating for days, especially if it rains a little.
• A gallon lasts a long time. I've done about forty stones and I'm still on my first gallon. That's maybe $60 total.

Cons:

• It's slow. You can't just spray and walk away expecting a perfect result in ten minutes. Sometimes I of to come back the next day.
• It doesn't work well in freezing weather. The bacteria go dormant. I've learned to only clean between April and October.
• It can leave a white residue if you don't rinse enough. I had a marble stone that looked chalky after one cleaning. I had to rinse it three more times to get the residue off.
• It's not a one-step fix for heavy biological growth. Thick lichen might need to be gently scraped off with a wooden or plastic scraper first, then treated with D/2.

Overall, I'd say it's the best option for a regular person like me. But you have to manage your expectations.

Common Mistakes I See Beginners Make (Learn From Me)

I've watched other volunteers at the cemetery make the same mistakes I did. Here are the big ones:

1. Scrubbing too hard. You're not scrubbing a pot. You're cleaning a hundred-year-old piece of carved rock. Light pressure, soft brush. Let the D/2 do the work.

2. Using too much water. D/2 needs to sit on the surface to work. If you keep spraying water on it, you're just diluting it. Wet the stone once, then spray D/2, then leave it alone.

3. Cleaning in direct sunlight. The solution dries out too fast and leaves a crust. I always clean in the morning or on a cloudy day.

4. Not testing on an inconspicuous spot first. I know, I know, everyone says this. But I've seen people spray D/2 on a crumbly sandstone and then watch it flake. Test a tiny corner first.

5. Expecting instant results. This isn't a magic eraser. It's biology. It takes time. I once cleaned a marble stone that took four applications over two weeks. The final result was beautiful, but it wasn't quick.

Frequently Asked Questions

Q: Can I mix D/2 with bleach to make it work faster?

A: No, please don't. Bleach kills the bacteria in D/2. You'd be wasting your money. Plus, bleach can damage stone over time. Stick with D/2 alone. If you need something stronger for a stubborn spot, try a second application of D/2 instead.

Q: Will D/2 damage old sandstone or marble?

A: In my experience, no. I've used it on sandstone from the 1800s and marble from the 1920s. The key is to use a soft brush and light pressure. But always test on a small hidden area first. Some sandstone is very soft and might crumble no matter what you use. If the stone is already flaking or powdery, don't clean it at all — call a conservator.

Q: How long does one gallon of D/2 last?

A: I've cleaned about forty headstones with one gallon. That includes full-strength applications and some re-treatments. If you're just doing one or two family stones, a quart would be plenty. The concentrate lasts for years if stored in a cool, dark place.

Q: Do I need to seal the stone after cleaning with D/2?

A: Generally, no. Most stone doesn't need sealant, and some sealants can trap moisture inside, causing damage. I never seal any stone I clean. Just let it dry naturally. If you're worried about future growth, you can spray D/2 once a year as a maintenance treatment — that's what I do.

Q: What should I do if D/2 leaves a white film on the stone?

A: That's usually from not rinsing enough, or from hard water reacting with the solution. I've had it happen. Just rinse the stone again with clean water and a soft brush. If the film is stubborn, mix a little distilled water with white vinegar (a tablespoon per gallon) and rinse gently. But test that on a small spot first. Usually, plain water does the trick.