Smoke is a lot more then that dirty, grimy, smelly film that covers the face of your marble surround and mantle.
You might be surprised to know that this smoke film is acidic and not only causes discoloration, but corrosion as well.
Your risk for etching the surface of your marble grows by the amount of time that smoky films goes untreated. Here’s what you need to know.
How Does Smoke Impact Your Marble Surround?
In a nutshell, smoke contains remnants of fuel that didn’t burn. As an example, residential wood smoke, per studies by the EPA, has PM2.5 (particulate matter less than 2.5 microns), carbon monoxide (CO), toxic air pollutants (e.g., benzene and formaldehyde), and climate gases (e.g. methane and black carbon).
It’s these small particles that make smoke visible on your marble fireplace surround and they also include small droplets of wood tars.
The rapid cooling of these particles when your fire goes out — a by-product of incomplete combustion — is what leaves a film and odor and penetrates this porous natural stone.
The smoke originating from a fireplace is classified as “driven smoke” meaning that when it shows up on a vertical surface, it’s because energy and pressure is behind it — this does not bode well for a porous marble surface.
Smoke on a horizontal surface, like a marble hearth would be considered “free-floating smoke” — driven smoke that has lost its energy and has settled on rather than being forced into a marble surface.
Steps in Cleaning a Marble Fireplace Surround
Because, as noted above, smoke can penetrate a marble’s surface and is corrosive due to its acidic properties, it requires a little more effort than normal maintenance to remove it.
Here are several different methods to tackle that dirty, oily marble surround film — starting with the easiest first, and scaling based on the severity of grimy film you need to remove:
- You can start initially by cleaning with warm, soapy water using a mild pH-balanced dishwashing liquid like Dawn® or some other neutral detergent. If this doesn’t cut through that oily smoke film go to the next step below.
- Scrub the surface of the marble with a plastic or natural bristle-type brush using a homemade solution of 4 parts water and 1 part hydrogen peroxide. Hydrogen peroxide is a very weak acid-type solution with very mild bleaching properties — it is as close to neutral on a pH-scale as a pH-balanced dishwashing liquid. Thoroughly rinse the marble fireplace surround with distilled water until streak-free and wipe with a dry cotton cloth.
- If smoke staining residue or yellowing can still be seen (based on how long the smoke has been allowed to permeate the surface) you can use mineral spirits (or white spirits for our UK friends) in equal parts with distilled water and spray on the surface. Mineral spirits work to break up oily stains.
- There is also the Trisodium Phosphate (TSP) option. TSP is a powdered cleaner used for removing tough, hard to clean dirt. TSP is specifically formulated for removing smoke smell, soot and smoke residues. Use 1/4 cup TSP in 1 gallon of warm water. TSP is a skin irritant and should be used only wearing gloves. It will not harm a polished or honed marble finish.
Understanding why smoke soot is not just any other household maintenance nuisance is the key component in how to clean a marble fireplace — and in how to protect your investment in this beautiful natural stone.
Because smoke film can corrode a marble’s finish and possibly lead to the need for repolishing, resealing or resurfacing, it’s best to incorporate the cleaning of your fireplace surround on a more regular basis — in lieu of only “seasonal” cleaning many get.