How to remove a mosquito candle stain on leuders stone?

Q. I have an outdoor fireplace that has leuders stone for the bench in front of the fireplace. The stone is a light gray / off white color, and I recently spilled citronella oil on it. We had a mosquito candle on top of the fireplace, and it completely melted during a hot day. When I went to pull it off the top of the fireplace it spilled on the bench and created a large stain, probably 1 foot in diameter.

I've recently been working with a stone cleaning guy, but he has not been able to remove the stain completely. He has tried a degreaser, two different types of poultices: dish soap and a laundry stain spray. The stain was getting lighter over the last few treatments, but recently darkened. and I'm concerned he isn't going to be able to fix it. 

Do you have recommendations of stone cleaners or other approaches I can try to remove the stain? Thanks for your help and having such an informative website!

A. Thank you for your kind words regarding our site. We take pride in being a valuable resource for home and property owners, as well as surface restoration professionals. 

Candle wax can be a bit of a challenge to remove after it drips onto stone surfaces. The wax can harden on top and even seep into the tiny pores of the stone, so you’ll want to remove both the surface wax and anything that’s soaked in. If there’s any staining left behind, that can be treated, too.

Start by scraping off any hardened wax using a plastic scraper or something similar that won’t scratch the stone. Avoid metal tools, since they can easily leave marks.

If wax has melted into the stone, get a hot iron and some white paper towels. Lay a paper towel over the wax spot and press it with the iron. The heat will melt the wax, and the paper towel will soak it up. Keep switching out the paper towels for clean ones until no more wax shows up.

Once you’ve gotten most of the wax out, dampen a clean cloth with water and add a few drops of ammonia or a degreasing cleaner. Wipe down the stone to remove any leftover residue, then rinse with clean water and let it dry.

If you still see a stain after that, you’ll need to use what’s called a poultice to pull it out. A good option is a poultice made with 40-volume hydrogen peroxide (the kind used in hair coloring, not the drugstore version). Spread it over the stain and let it sit for a while so it can draw the discoloration out of the stone. If the stain starts to fade, that means it’s working—just reapply until it’s gone. If it doesn’t budge after a few tries, try making a new poultice using paint thinner instead of hydrogen peroxide. For detailed, step-by-step instructions on how to mix and apply a poultice correctly, check out our free Stain Management App.

After you’re done, the area where you applied the poultice might look darker than the rest of the stone, but that’s just moisture—it’ll even out once it’s completely dry.

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.]