Cleaning marble slab walkway

Question

I have pieces of marble  that I use for a walkway outside. They have green and dark blackish areas from being under decaying leaves for a couple of years. I tried  muriatic acid diluted with water, but it did little - I used a broom as I didn't want to get too close.  Can anyone help me? At this point, I am not too concerned about damaging them as they are already damaged.

Janet Pizaro · Answer

Try a product called Wet and Forget available at Home Depot in the paint department.

FRED RIGGS · Answer

I would use a pressure washer.  I use it on our regular sidewalk, and makes them look new and fresh, compared to the other homes.  Wet and Forget might help, but follow it with a good pressure washing.  Use one with 2100 psi.  Muratic acid just disolved part of the surface.  Wrong thing to use IMO

Cindy Hagemann · Answer

I agree with Fred - use a pressure washer - they will be clean in a jiffy!

Sam · Answer

A pressure washer will get it all out. You won't even need any soap/detergent.

Dale Barnes · Answer

Plain Old Hydrogen Peroxide.  You can purchase by the gallons.  I tried pressure washing, Wet and Forget, White vinegar and bleach.  Hydrogen Peroxide was the only thing that got mine completely clean.

FRED RIGGS · Answer

Bleach is dangerous, You can put the pressure washer on needle spray so you do not disturb the stone dust. Ask your pharmacist to order H202 for you in gallons. Oh, that is peroxide. Wear old clothes, peroxide is a bleach, like you brush with sometimes, clean wounds with it also. Don't leave the cap off.  Oxygen and light will deteriorate it.

Dale Barnes · Answer

Yes, I cleaned Marble and also Saltillo Tile with Hydrogen Peroxide and Saltillo is so porous that the mildew really gets in there.  I used a garden sprayer full of straight hydrogen peroxide and sprayed it on and wet it thoroughly.  Then I let it sit for about 20 minutes while it bubbled up.  I was doing a very large patio area so I then took a push broom and was able to get most of it up on the first try.  It was gross.  There were a couple of particularly bad areas I had to spray again but your marble is not nearly as bad as was mine.  Hydrogen Peroxide is a natural product and also does not hurt the environment.  Just google Where can I purchase hydrogen Peroxide by the gallon and numerous places will come up.  That is what I did.  Good luck.

Phil a · Answer

Marble, like most natural stone, is permeable, meaning it will pass water/moisture through. That is why it, and other stone surfaces, have to be sealed when used for counter tops, so oil and water stains won't form. It looks like your stones are laid in dirt. That might be the cause, allowing moisture, with the dissolved minerals and salts from the dirt, to wick from the bottom to the top. If not sealed, stone, especially white stone like marble, should be laid in a gravel or sand bed, not dirt. I have a feeling the stones are stained from underneath and no amount of surface cleaning will get rid of it.  Let us know what you find out. Phil

Inetia · Answer

There's always spray paint.

Bon7229865 · Answer

Try the product 'Spray and Forget'. It doesn't work immediately but over time the black will be gone and the producthelps keep the stone clean for a while. Find it in the paint Dept of home depot.

Pamela Robertson Pullmann · Answer

I would use bleach water and a stiff brush. Since these are outside I don't see any real harm from using the bleach. A 2 parts water to 1 part bleach should work fine. The bleach will kill any bacteria that is growing on and dis coloring the stone. 
If you need something that has some grit to it, make a paste out of baking soda and water and, using a stiff or wire brush, just work it over the stone and rinse. 
Good luck!

Ruthanne Brann · Answer

Thanks for all the suggestions.  I used my already diluted muriatic acid without wetting the marble first and it worked better.  Then I tried Comet with bleach and a hand brush and that worked even better.  Finally I went to town (literally) and bought a gallon of bleach, a sponge mop at the Dollar Tree Store and a deck scrubbing brush/broom with a long handle at Kmart.  I applied the bleach directly with the cheap sponge mop and then gave it a little scrub with the deck scrub 'broom.'   I let it sit a little while and then rinsed it off.  So, it ended up that in consideration of expense, exertion, and the imperfect condition of the marble to begin with that plain old bleach was the best for me.

Amazing · Answer

BLEACH, MUSCLE POWER AND MAY NEED A POWER WASHER

Cleaning marble slab walkway

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Cleaning marble slab walkway

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