Cleaning and Polishing Marble Surfaces with Baking Soda?
Some of the latest trends online is to “Polish Marble with Chalk” or Polish Marble with Baking Soda”. These ‘remedies’ are dubious at best, and can actually harm sensitive marble surfaces.
Chalk is actually mineral Talc. Talc is the softest of all minerals as listed on the Mohs Scale of Mineral Hardness. Talc is listed at harness “1”. Most marble used for building materials is in the hardness range of ‘4-6’, while some may be as soft as ‘3’.
When we polish marble in our shops or in the quarry factory, we use harder abrasives than the surface we are polishing. The abrasive bricks are used in progressively finer and finer grits until a hard mineral ‘reflects light’, this is what makes a polished marble shine.
Most marble becomes dull either by foot traffic-abrasion, or by acids or other chemical cleaning products that actually etch the surface, causing microscopic pitting, making the marble less smooth, which manifests as appearing dull. By using talc or chalk alone, without smoothing out scratches and deeper abrasions, it would take hours and hours of polishing with talc to see any measurable difference in shine, because it is too soft.
Baking Soda is a basic with a pH of 9 which can dull sensitive marble surfaces with continuous use, as it is abrasive. See post on how Baking Soda can harm teeth (calcium based). If baking soda is bad for teeth, why do some suggest using it on marble, another calcium based stone?
Ammonia is very bad for marble as it has a pH of 11.6 and will burn (etch) polished marble surfaces.
Fortunately, there are commercial products available for restoring marble either using polishing waxes (for floors in good condition), or mild polishing pastes that finely smooth out marble and add waxes and conditioners to effect the shine of dull marble.
One option is to use HMK P19 Marble and Granite Polish. By adding P19 to mop water and following up by gently buffing, this will add brilliance and shine to stone floors in good shape.
If your marble surface has scratches or deep wear then you may need to use a more abrasive polish like P21.
HMK P21 is a Professional Stone Care product from the world leader in Stone Care.
P21 is a polishing paste that can be used to polish out etch marks in marble, as long as they are not too deep. If you rub your finger over the etch mark and feel a soft depression or heavier texture, then you may need to gently smooth out area first with fine silicone carbide sandpaper (wet-dry) in 400 grit then 600 grit.
Wet sand area with a small sanding block in circular motions until smooth, then move to 600 grit and repeat. Apply P21 Marble Polish to a soft white cloth and apply in circular motion to area. Buff vigorously adding more polish if needed.
Immediately, use clean area of cloth to buff to a shine. If residual dulling remains, use more P21 Polishing paste and repeat buffing action.
For regular cleaning always use a pH neutral cleaner like HMK P24 Liquid Stone Soap. This maintenance cleaner will clean and condition with regular use, and not harm the surface like high pH cleaner can. Most dish soap is pH 11-14 to effectively clean dirty dishes and pans, but NOT good for marble surfaces.
These products can greatly enhance the look of moderately dull marble surfaces with regular use. If you need assistance with your stone, please contact Torin Dixon at 800-380-6881 or email at firstname.lastname@example.org