How to remove grease on sandstone?

Q. We had a beige sandstone countertop installed for an outdoor kitchen. It is sanded smooth and was sealed with three coats of sealer. I don’t know what kind—just said “sealer” on the can. Some was spilled on our manufactured patio pavers, which we thought would have to be replaced, but after using a power washer, the stain was pretty much gone. I only mention that to let you know it might not be the best sealer. Grease and oil leave spots that we can’t seem to get out. We’ve tried pretty normal things to remove them, and most don’t work or actually leave a worse stain (we tried a solvent and enzyme-based cleaner). This stone is so easily marked it even stains from rainwater. I would love to know how to remove the oil/grease stains and red wine, which will inevitably happen, and if we can use something that will do a much better job sealing it.

A. To remove stains from sandstone, you’ll need to use a poultice of hydrogen peroxide mixed with an absorbent material such as diatomaceous earth. The hydrogen peroxide works as a mild oxidizing agent that helps lift organic stains like oil, grease, and wine from the porous stone. Use 40-volume or 12% hydrogen peroxide, available at beauty supply stores, not the regular strength peroxide used for wound care. For detailed, step-by-step instructions on how to mix and apply a poultice correctly, check out our free Stain Management App. Repeat poultice applications if necessary since some deeper stains may take multiple applications to fully disappear.

Now, let's talk about sealing your stone. Before applying any new sealer, it’s important to identify the existing sealer. If the existing sealer is a penetrating sealer (which soaks into the stone and provides protection from within), a new application of penetrating sealer can be applied. If it is a topical sealer, which forms a film or coating on the surface, it will need to be completely removed before applying a new product. Otherwise, it might trap moisture or stains beneath it, making cleaning more difficult. We highly recommend hiring a professional stone restoration contractor to remove existing sealer using a stone-safe stripper or by lightly honing the surface. To find a vetted PRO in your area, visit www.surfacecarepros.com and click on Find a PRO. 

For outdoor use, sandstone should ideally be sealed with a high-quality, breathable penetrating sealer specifically formulated for natural stone. Look for one that offers resistance to both oil-based and water-based stains and is rated for exterior environments. These sealers help protect the stone without altering its natural appearance. 

Because sandstone is very porous and soft, it’s prone to staining and weathering. Routine maintenance—such as quickly wiping spills, periodically reapplying the sealer (typically every 1–2 years outdoors), and cleaning with a pH-neutral stone cleaner—will greatly extend its appearance and performance.

If the stains persist or you’re unsure about the existing sealer, contact your stone PRO. They will test the stone, identify the sealer, and perform the optimal restoration and sealing process to bring back the natural beauty of your sandstone.