Cleaning Stone

[jonnyrocketboots]

Hi all just looking for a little advice on getting stains out of stone here without damaging it.

Ive managed to smear some soot into quite an expensive marble hearth.  I Have tried soap and water to no avail as the soot has got 'into the grain' so I think I need something to lift the soot out without damaging the stone. Vinegar has been suggested but I'm not won over.

I bought some 'proper' cleaner today but having looked at the ingredients;

contains;

cationic surfactants <5%

preservation agent: methylchloroiso-thiazolinone,

some methylisothiazolinone

and a dollop of dimethylol glycol for good measure!

Doesnt sound very good for porous stone to me!!

Appreciate anyones thoughts in return before I set about trashing a beautiful bit of stone!

I need something that will lift the dirt out without damaging the stone itself. No vinegar or fancy chemicals required!!

Thanks y'all!

 

[Laurie]

Limestone/marble is mainly attacked by acids.
Soda based alkali products should do it no harm.

 

[JasonC]

No personal experience, but Google may be your friend ?
http://www.oldhousejournal.com/cleaning_a_marble_mantel/magazine/1020
http://www.ehow.com/how_5663825_clean-soot-marble.html

 

[droid]

Here's a firm that supplies limestone for decorative purposes:

http://www.lowesmarble.com/Maintenance(1782996).htm

 

[robjones]

Might want to consider seeking advice from a sculptural conservator in a major museum (V&A maybe?) - marble is porus and light coloured marble can be very tricky to clean. Most conservators will give you a few minutes on the phone for free but lengthy advice may well be changed for in the current climate / current polital regieme (discuss!).

Photos of the stone will be crucial as the commerical / general term 'marble' includes a many lithologies that geologists would term something else.

Alternative: wipe soot over it all...

 

[Pitlamp]

Was it dry soot or soot mixed with water? If the former, then the carbon particles will have settled into the (microscopically) rough surface which appears smooth to the naked eye.

So - maybe dry clean it? By this I mean blow it with compressed air and use a fine dry brush? (No chemical involvement there to cause damage.)

I agree with the comment above - probably best to avoid anything acidic (or at least do so only with expert advice). If it's a really important job, don't rush. Take the time to get the best expert opinion.

Is turning the marble slab over an option?

 

[grahams]

I've been pondering the very same problem since we moved into our new house. Our fireplace is a massive chunk of green sandstone and the carbon from the wood burner cannot be washed out. As Pitlamp says, the carbon will only be in the surface but, as carbon is virtually unreactive at room temperature and will not dissolve in any CaCO3 friendly solvent, removal is difficult.

You'll probably therefore need to remove the surface and re-polish using carborundum powder and tin oxide respectively. These can be obtained from rock polishing suppliers at very low cost. Carborundum powder is supplied in various grades of coarseness. The finest grade gives a matte finish that is smooth to the touch and can then be polished using SnO on a leather cloth.

I should try this method at B&Q (or purchase one of their marble tiles) before committing yourself.

Disclaimer: if it turns into a mess, don't blame me.

 

[Bottlebank]

I wouldn't try this on marble but we removed our sandstone fireplace and I got it sandblasted, and then rebuilt it. It worked a treat.

 

[grahams]

I wouldn't try this on marble but we removed our sandstone fireplace and I got it sandblasted, and then rebuilt it. It worked a treat.

Cheers Bottlebank - that solves my sandstone cleaning problem. 

 

[Bottlebank]

No probs, but likewise don't blame me if the chimney collapses when you remove the lintel

pm sent with a little more detail.

 

[jonnyrocketboots]

Thanks for helpful tips guys, going to buy a small piece and rub some soot in so I can try a couple of things. Good ol Google suggests bicarbonate of soda with a little water. Failing that I'll give the 'special' cleaner a whirl. Just the sound of the chemicals in it puts me off.
Cheers
JRB

 

[Pitlamp]

Is it worth asking a monumental mason what it'd cost to take a few thou off and re-face it?

(Or is that plan C in case other approaches make a right mess?!)

 

[Spike]

Is it worth asking a monumental mason what it'd cost to take a few thou off and re-face it?

Monumental Mason? Like Gutzon Borglum perhaps?

Yes, that's my coat. The one with the Mount Rushmore postcard in the pocket...

 

[Pitlamp]

Use a pressure washer?

 

[bograt]

I wonder whether a tin of Nitromorse and an old toothbrush may be your friend here? It is caustic based so should'nt affect marble, but check it on a scrap bit first.

 

[jonnyrocketboots]

Hi chaps, Fire is mounted to the marble plinth so it would be a right royal pain in the hearth to take it all outside to try pressure washing.

I did look at 'Wikihow' which suggested a flour and water poultice, so I mixed some up quite thick, smeared it on and covered  with cling film and left for 24hrs.  It did lift some ash out but has cleaned the rest of the fireplace up a treat.

While I was a bit pissed off with myself for staining an expensive fireplace I've now gotten over it and think it actually adds character!  Doesn't look so brand new anymore!  Might just go and accidentally drip some candle wax on it now for real authenticity!

Cheers for suggestions tho guys! 

p.s. Is 'gotten' even a word or did I just make one up? 

 

[Laurie]

p.s. Is 'gotten' even a word or did I just make one up? 

Gotten is the old 'Elizabethan' word for 'got'.
It's still used widely in the US.