Those look like etch marks that have soiled over time.
I would
Abrade the surface using silicon carbide abrasives such as sandpaper.
Electroplated diamond
Pads may also be quite effective .
After abrasion try using an oven cleaner without lye. If there is anything left after sanding.

Sent from my iPhone

On Dec 5, 2016, at 2:52 PM, marblerenu@aol.com (via sccpartners list) <nobody@simplelists.com> wrote:

You may want to try a poultice with Drytreat's Oxyklenza. Possibly Klenztone #4 as a deep cleaning topical cleaner.

Tim Lesnar
Classic Marble Restoration 612.250.0041 (c)
Sent from my T-Mobile 4G LTE device

------ Original message--- ---
From: Doug Smith
Date: Mon, Dec 5, 2016 1:41 PM
To: sccpartners@stoneandtilepros.simplelists.com;
Cc:
Subject:Limestone Hearth

Hi Partners,

We have a consumer that has a stain on his Hearth (see pics).
At the suggestion of some of our Partners he has tried:

1. A low level Peroxide and the stain lightened somewhat
2. Then.....a Hearth Cleaner and the stain lightened even more.

We are looking to see if there may be another solution that may help erase the stain completely.
Please see pics attached of his progress in removing the stain.

If you have any additional ideas please let me know.
Also, if you need more info as well.

Thanks much,

Doug



--
Doug Smith
Stone and Tile PROS/Id Est Productions
15155 W. Colonial Drive
#783968
Winter Garden, FL 34778
877-842-8249, Ext. 727
407-754-4560 Direct Line
 Visit list archives, subscribe, unsubscribe or change your subscription preferences:http://stoneandtilepros.simplelists.com/sccpartners Start a new conversation (thread): sccpartners@stoneandtilepros.simplelists.com
 
Visit list archives, subscribe, unsubscribe or change your subscription 
preferences:
http://stoneandtilepros.simplelists.com/sccpartners
 
Start a new conversation (thread): 
sccpartners@stoneandtilepros.simplelists.com