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Reba asked: How do I clean my stone fireplace? It is different sizes of stone and mortar and has never been cleaned.
If 
you don’t want to hire a professional chimney sweep to clean your stone fireplace, the following method should work well for the do-it-yourselfer. Keep in mind that stone is a porous material, and cleaning it may require quite a bit of physical scrubbing to reach all of those nooks and crannies!
You Will Need:
- Hand broom and dustpan or vacuum
- Trisodium Phosphate (TSP) heavy duty cleaner – available at most hardware stores.
- Bleach
- Warm water
- Bucket
- Sponge
- Stiff bristled brush
- Old blankets or towels
- Plastic tarp
- Duct tape
- Rubber gloves
- Eye protection
Steps to Clean the Stone:
- Wear rubber gloves and eye protection at all times.
- Sweep of vacuum up as much dust as possible from outside the fireplace.
- Mix a solution of TSP (trisodium phosphate) in warm water in the bucket according to package directions. The dirtier your fireplace, the stronger you want to make your solution.
- Add 2-3 ounces of bleach per gallon of solution.
- Lay the plastic over or around the hearth to protect the underlying floor. Seal around the edges with duct tape to prevent leaks.
- Pile blankets and/or towels around the area to catch runs, drips, and overflow as you scrub.
- If the fireplace is heavily soiled, wet it down with the solution using a sponge to allow the detergent to begin working before you start to scrub.
- Next, attack with the scrub brush. Deep, hard scrubbing will be required on porous stone. Eye protection is very important here, as the scrubbing process will send droplets flying! You may want to keep your mouth shut as well.
- If stains are persistent, make a paste of water and TSP and apply directly to the stone. Scrub liberally.
- Finish by sponging clean water over the stone, from top to bottom, as a rinse.
- Once you’re satisfied with the cleanliness of the stone, allow it to air dry before removing the blankets, towels, and plastic.
Additional Tips and Advice
- Never attempt to clean a stone or brick fireplace with a flammable liquid. It will be impossible to remove it, and the residue left so close to an open flame is a serious fire hazard.
- Bleach may fade stone, so use it carefully and sparingly.
- If streaking occurs, you need to use more water. The cleaner spots are those which were wetter where the water ran down from higher points on the stone.
- It’s always a good idea to test any cleaning solution in an inconspicuous spot before beginning the project. Wait 24 hours, or at least until the test spot dries, before taking on the rest of the project.
- Work on a cold fireplace. Do not attempt to clean a heated fireplace or one in use.
- To avoid a bigger mess, scoop out all ash and fire debris before cleaning the face of the fireplace.
Our stone mason did not clean the mortar off the stone and now they look cloudy. I need to clean it. The only thing I’ve heard of was muriatic acid and I’m scared of that. Can anyone help?
Charlene,
You can try using dish soap and water, and scrubbing the stone with a scrub brush.
You can also try scrubbing the mortar with sugar water.
Vinegar is acidic and can be used to clean mortar off of stone. Make a 1:10 mix of vinegar in water, spray the solution on the mortar and allow the vinegar water to sit for several minutes before scrubbing.
Source: eHow – How to Remove Mortar Smears From Manufactured Stone
Source: eHow – How to Clean Mortar Residue Off of Flagstone
Source: eHow – How to Clean Dried Mortar from Tile
To clean a fireplace, I use clean soft water and scrub, and little dishwasher detergent because it can work on stubborn soot and dirt. Well, I try to follow the process mentioned above.
How do you get soot marks off of the stone surround? It is not granite; could be limestone. It is in a 1960’s multi-level house. Have already tried TSP and peroxide. Maybe not scrubbing enough? Anything else we should try? The soot marks above the firebox really make the stone look dingy.
Thanks.
How do I remove a stain which looks like paint remover (spirit)?
Zoe,
This article might help: How to Remove Methylated Spirits (Denatured Alcohol) from Terracotta Tiles.
I use Scrubbing Bubbles and let sit for a few minutes, then scrub well with a scrub brush. For VERY HEAVY marks, I have had to do it twice (like soot at the top of the opening of the fireplace).
IMHO it helps to start off by removing the dust with a shop vac or a crevice tool and a standard vacuum cleaner, otherwise you are driving the dust and grime further into the porous surface just as soon as water/cleaner hits it. Vinegar and a large bristle brush is probably the gentlest way to clean after using the vacuum approach. Conceivably, one could add baking soda to vinegar for the foaming action, which might help to remove stains — but beware that the baking soda itself may leave behind a chalky residue if it isn’t rinsed off well.
Can I polyurethane my stone fireplace to make it shine? The stone is dull!
Barb,
Yes, polyurethane can be used on stone fireplaces. However, it is always best to ask a specialist (or at least someone working at a hardware store) for the best sealant for your specific type of stone and intended results (finish). Good luck!
Source: Hunker – What to Use for a Rock Fireplace With a Wet Look Finish
I have an Arkansas field stone fireplace. I want to clean it and not let the mortar joints get the residue from the field stone. Then I would like to seal it. Anybody have suggestions?
Help!
My red Yankee candle just fell off of my precast stone fireplace, crashing onto the precast base and living room carpet. I scraped the red wax off, but don’t know where to begin to clean the stain. It looks as if someone had thrown up on it. Is it better to call a professional? If so, who would know how to clean precast.
I’m desperate! Thank you!
Check it out! We’ve answered your question! Yay!
I have a couple of additions to the directions. I have a heavy rock fireplace and found that using a sprayer bottle to apply the solution and a firm toothbrush to get at the grout in between the rocks helps. The sprayer also works well to rinse.
Try “Goo Gone.” Haven’t tried it on stone, but it works on everything else for removing adhesive.
Goo Gone has an oil base and may stain stone.
I have a brand new cast cement fireplace (electric), and it has two dirty finger marks on it. The person that sold it to me told me to use soap and water, but that made it worse! Can anyone help me with a cleaning tip?
I have the same problem. The bumper was protection for my young children! Now I have marks from the sticky squares to hold it on. Did you ever find an answer on how to remove these? Thanks!
I removed a foam bumper from my brick fireplace hearth. How do I remove the sticky adhesive residue left behind?
To remove adhesive, use baby oil or mineral spirits.