Q. How do I get a motor oil stain out of my blue stone deck?
A. Motor oil is resistant to water-based cleaning. It also has certain properties that make it highly adhesive to surfaces, and its amber/black color can easily transfer into porous surfaces. A motor oil discoloration is both chemical and physical in nature, meaning the stain chemically bonds with the stone instead of just filling in the stone's pores. In other words, we're not at all surprised that motor oil caused a difficult-to-remove stain.
Bluestone is dense, but it has a porous, absorbent microstructure. Even when it is sealed, the surface of the bluestone may allow liquids like oil to wick inward.
To remove motor oil from bluestone, the first step is to absorb the excess oil. If the oil spill is fresh, blot it with paper towels or cover it with an absorbent material such as kitty litter, baking flour, or diatomaceous earth. Leave the absorbent material in place for several hours or overnight to pull as much oil as possible from the stone’s surface. Do not rub the spill, as this will spread the oil over a larger surface and make stain removal efforts more difficult.
NOTE: Follow the manufacturer’s safety precautions when using chemicals.
Next, clean the discolored area with a degreasing agent. Here's how. Mix warm water with a stone-safe degreaser. Avoid acidic cleaners, which can etch the surface. Gently scrub the area with a soft-bristle brush. Allow the solution to remain for 30 minutes. Rinse thoroughly with clean water. Let the stone to dry out.
If any discoloration remains, apply a poultice to draw out oil trapped in the stone. A poultice works over time and may need to be reapplied several times before the stain lifts completely. Your dry poultice ingredient will be poultice powder or diatomaceous earth. The chemical ingredient for your poultice will be degreaser. If a stronger chemical is necessary, use a solvent. Do not mix chemicals. For detailed, step-by-step instructions on how to mix and apply a poultice correctly, check out our free Stain Management App.
Once the stone is clean and dry, apply a penetrating stone sealer to help prevent future oil absorption. We recommend you hire a professional stone restoration contractor to select the most appropriate sealer and apply it correctly. To find a vetted PRO in your area, visit www.surfacecarepros.com and click on Find a PRO. Your PRO can periodically deep clean and reapply sealer to inhibit future staining and keep your stone looking fabulous all the time.
ABOUT THE AUTHOR Fred Hueston is the Chief Technical Director at SurfaceCarePROS.com and Director at StoneForensics.com. He is also the author of Stone and Tile Restoration: The Manual, a comprehensive online manual for stone and tile restoration contractors. [Learn more about Fred.]
Article ID: 806
Created: November 4, 2025
Last Updated: December 4, 2025
Author: Fred Hueston
Online URL: https://surfacecarepros.com/kb/article/how-to-remove-a-motor-oil-stain-on-blue-stone-806.html