How do I clean a cast sandstone and sandstone slab mantel?

Old 01-24-00, 09:13 AM
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I am trying to figure out the best way to clean and remove a few stains from a cast sandstone fireplace mantel. In general, it is just "usage" around the fireplace type smudges etc. However, there is a section that has some blue stains on the surface of it. If I had an email address I could send you a picture of the mantel and how it looked when asssembled before I got it. When it was pulled away, it is hollow behind on the uprights and the mantel top (where the carved look is). The base and the mantel shelving are solid sandstone. Any suggestions?
Old 01-24-00, 10:56 PM
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You could spend the time to learn how to make your own stone cleaners and poltices for removing the blue stain), but why go though that trouble when ready made products are at your disposal. And, they are almost mistake proof.

Use a Netural Soap (made especially for stone "Stone Soap") and a plastic or natual bristle brush for cleaning. Wet the stone, apply soap according to the directions, scrub and blot dry. Never rub stone to dry.
The same method applies to the cast stone. BTW, plain water will clean much of the grime away.

The Blue Stain:
After the stone is clean then the stain can be addressed. The first step is ID the stain and its origin. Think about what caused the stain.

Just guessing: the blue stain may be the result of contact with a plant fertilizer, ink, copper, bronze, a mineral stain, or not a stain at all. The notes below may help, but if a stain does exist, I suggest you take the pictures with you and purchase ready made products for removal. Ensure that all products may be used on sandstone by reading the directions before leaving the store. Where: marble dealer, stone shop, or one of the larger retail "do it yourself" stores.

Etching or hazing of the surface sometimes looks like a stain, but it is a defect resulting from a chemical reaction between a sealer and some object, cleaning compounds, and the stone or scuffing. Look across the surface using a stong light. If it looks alot duller than the rest, it may not be a stain.

A sealer, if present, must be removed (buy the product for removal). Check it again. A honed surface can be wet sanded with fine (800 - 2000 depending) Silcone Carbide wet or dry sandpaper plus water for a lubicant. For a polished surface purchase a ready made product for sandstone.

Mineral stains can be tough. Some cannot be removed, others will lighten, only few can be completely removed. They occur when minerals within the stone react chemically with another substance. Suspect a mineral stain when other type of stains have been excluded. For mineral stains ask the dealer. Some products contain strong acids or bases, and other compounds, and must be carefully monitored during application.

Oil based stain: purchase a poltice.
Water base stain: purchase a poltice.
Metallic stain: "Iron Out" (product name).
Other types of stain: ask the dealer. There are too many possiblites to list.


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