How to Clean a Slate Hearth

Co-authored by Michelle Driscoll, MPH

Last Updated: September 2, 2021 References

If you have a slate hearth around your fireplace and it’s been there for more than 2 months, it’s probably a little dirty. Slate fireplace hearths need to be cleaned regularly to prevent and remove the grime and stains that build up on them. Luckily, cleaning a slate hearth is simple to do with some basic household supplies. Check out the tips below to learn how to clean a slate fireplace hearth and remove stains from a slate hearth so your slate fireplace looks brand new again.

Method 1

Method 1 of 2:

Slate Fireplace Hearth Routine Cleaning

1
Sweep, dust, or vacuum the slate to remove any loose dirt. Remove any dust, ash flakes, or other debris items from the surface of the slate hearth before you proceed to clean it with the dish soap mixture. You can also use a dry mop if you have one.^{[1]
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- Make sure you remove any dust or dirt in the grout trenches between the slabs of slate as well.
2
Make a cleaning solution out of water and dish soap. Mix a few drops of mild dish soap into a bucket filled halfway with warm water. Use a long wooden spoon to stir this mixture together until the dish soap is completely mixed with the water.^{[2]
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- Use a mild dish soap to avoid inadvertently damaging the slate on your hearth.
- You can also use an all-purpose surface cleaner if you don’t have any mild dish soap.
- Avoid using a bucket that’s too small. You should mix the dish soap with at least 2 cups (470 mL) of water.
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3
Scrub the slate with a cloth or mop soaked in the soapy water mix. Dip your cloth or mop into the mixture, then ring it out slightly to get rid of excess moisture. Then, scrub the slate using circular motions to clean it.^{[3]
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- Don’t apply too much pressure when you go to scrub the slate. If a gentle once-over isn’t enough to clean off any dirt and grime on your hearth, use a more powerful cleaning solution instead.
- Pay special attention to the corners, as this is where a lot of grime can build up unnoticed.
4
Rinse the slate with clean water to get the soap off of it. Spray small amounts of water onto the slate with a spray bottle in order to rinse the hearth without making a mess. You can also use a sponge soaked in clean water if you don’t have a spray bottle handy.^{[4]
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- You should also allow the hearth to air dry overnight if you intend to polish it after you clean it.
5
Use a clean towel to dry any excess moisture off of your hearth. You can use any ordinary towel to dry the slate, so long as it’s clean. If you plan to do any further cleaning, allow the hearth to air dry overnight first.^{[5]
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- Get as much of the water off of the slate as possible. Any excess moisture left on the slate may cause water stains.
6
Wipe down the slate with teak oil to polish your hearth. Use a soft cloth to apply a thin layer of teak oil to the surface of the slate. Then, use a second clean cloth to remove any excess oil from the surface.^{[6]
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- You can buy reasonably priced teak oil at most large hardware stores.
- You can also use slate oil instead of teak oil, although the former is usually more expensive and a bit harder to find in stores.
- Teak oil also helps hide scratches on your hearth, making it easier to seal.^{[7]
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Method 2

Method 2 of 2:

Removing Stains from a Slate Fireplace Hearth

1
Make a cleaning solution out of hydrogen peroxide and water. Mix equal portions of water and hydrogen peroxide in a small spray bottle. If you don’t have a spray bottle, you can also mix these ingredients in a bucket and use a sponge to apply it.^{[8]
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- You can also use a mixture of equal parts of baking soda and hydrogen peroxide to provide stronger cleaning power.
- You may also use 1 part rubbing alcohol with 8 parts water as an alternative.^{[9]
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2
Spray your mix of water and hydrogen peroxide onto the stain. Apply a thin layer of the water and peroxide mixture directly to the surface of the stain. Let the mixture sit for 5-10 minutes before proceeding.^{[10]
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- Avoid spraying this mixture near any colored grout, since the bleach in the mixture can discolor your grout.
3
Scrub the stain with a soft scrub pad or brush. Scrub in a circular motion without applying too much pressure in order to clean the slate without damaging it. If you used baking soda and hydrogen peroxide instead of the water mixture, use a moist cloth to scrub the slate.^{[11]
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- Refrain from using steel wool, as this might cause damage to the slate.
4
Allow the slate to air dry after you’ve scrubbed the stain clean. There’s no need to wipe the solution off of the slate after you’re done. For best results, allow the slate to dry overnight before putting anything on it or using the fireplace.^{[12]
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5
Use a Trisodium Phosphate (TSP) mix on tougher stains. Make a cleaning paste out of TSP and water, carefully following the manufacturer’s instructions for use. Spread the paste onto a sponge and use that sponge to scrub the slate. Finally, soak a separate clean sponge in water and use it to remove any residue from the slate surface.^{[13]
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- This method is particularly useful if the stains on your slate were caused by smoke or soot.
- You can also use a commercial fireplace cleaner to help remove soot and smoke residue.^{[14]
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Community Q&A

Question

I have a water stain from a flower container that leaked. I have gotten most of the dirt stain off, but now have a gray stain. Any advice?

Community Answer

Try baking soda on a scrub sponge and see if that will help. Use it dry, and you may have to do it more than once.

Warnings

Avoid using acidic cleaners, like vinegar, since they can etch and damage the slate.^{[16]
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Don’t let water pool up on your slate since the water will absorb into it.^{[17]
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