How to remove black candle wax from a stone fireplace?

Q. How do I get rid of candle wax (black) on a stone fireplace?

A. Black candle wax can be frustrating to remove, especially on a porous surface like stone. There are usually two challenges to address: the wax itself, which can seep into the stone, and any dye in the candle, which may leave behind a stain. Thankfully, chances are that both issues can be fixed with a little patience and the right approach. 

There are a few things you should know before you begin. The type of stone you have can greatly affect the effectiveness of the wax removal process and how well a poultice works. Test any chemical on a hidden area first, especially on polished, colored, or treated stones. Marble, limestone, travertine, and other calcium-based stones are susceptible to etch damage when exposed to acidic substances. Granite is less porous but may still stain. Slate has an uneven surface and may need repeated treatment. Sandstone is very porous and may require multiple poultice applications. If the stone has a sealer or coating, be aware that certain chemicals may strip or damage dyes. Always test cleaners in an inconspicuous area first.

Since we don’t have specific details about the type of stone you have, its finish, or any coatings that may have been applied to the stone, the following steps are only general recommendations meant to work across most situations.

1. Start by scraping off the solid wax using a plastic scraper or credit card. Avoid metal tools to prevent scratching. This applies to all types of stone, including polished, honed, cleft, sealed, or unsealed.
2. Next, to lift wax from the pores, place a white paper towel over the affected area and apply a clothing iron on low to medium heat over the towel for a few seconds. NOTE: Use an iron you don't mind getting wax on. The idea here is to melt the embedded wax and then allow the paper towel absorbs it. Repeat this process using fresh towels each time until no more wax is pulled up.
3. For remaining wax residue, dampen a clean cloth with water, wring it out, and add a few drops of degreaser or ammonia. Gently wipe the area, then rinse with clean water and let it air dry.

Hopefully, the wax removal process will result in the removal of any staining agent, as well. If a stain from the candle dye remains, you can remove it using a poultice, which is a mixture of a chemical and an absorbent medium that draws the stain out of the stone over time. The poultice ingredients we recommend are 40-volume hydrogen peroxide (you can purchase this at a beauty supply store) and diatomaceous earth. For detailed, step-by-step instructions on how to mix and apply a poultice correctly, check out our free Stain Management App.

Let your poultice sit for 12 to 24 hours, and then remove and rinse. If the stain persists, repeat the poultice application using paint thinner instead of peroxide. Be sure to follow the paint thinner manufacturer's safety instructions.

We also recommend you have a professional stone restoration contractor clean and reseal the stone if needed, especially around the firebox. To find a vetted PRO in your area, visit www.surfacecarepros.com and click on Find a PRO.

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.]