Q How can I remove a candle wax stain from my concrete paver patio? Most of the visible wax has been removed, but dark stains remain.
A Once the visible candle wax is removed, what often remains is a greaselike stain. Because concrete is so porous, the stain probably has penetrated the pavers to some degree. To remove it, try physical removal or a poultice.
Physical removal is tidier and it's easier to see whether you're being effective, but the process is a little wacky. (If you have neighbors who might report you to the authorities, inform them of what you plan to do.)
Cut several paper bags so they will lay flat. Place one on the stain, or use several layers of paper towels. Take a clothing iron and plug it in to heat. (If you don't have an electrical outlet near your patio, you'll need a long extension cord.)
When warm, place the iron on the bag that sits on the stain. Lift and you should see a "wet" spot where the warmed wax has transferred to the paper. Experiment with the length of time you let the iron sit on the paper. Once you see the stain on the paper, lift paper and replace with a clean paper bag section and repeat. Continue until little or no stain transfers to the paper.
If the paper bag trick doesn't do the job, or if you'd like to avoid ironing your concrete pavers, you can try the poultice method.
Poultices are commonly used to remove grease stains on concrete pavers from outdoor grilling. A poultice reverses the natural absorption process. Absorbing powder poultices contain chemicals mixed with water and are available from most stone suppliers. You can also use a whitening powder mixed with a chemical to form a poultice. A stone supplier can recommend the best ones for your pavers. Products generally are available at building supply or hardware stores.
Once you determine which type of poultice to use:
• Wet the stain with distilled water. This will isolate the stain and intensify the removal process.
• Mix the poultice into a thick paste (about the consistency of peanut butter) and use a wooden spatula to apply a layer about a quarter-inch thick over the stain.
• Cover the poultice with plastic wrap and tape the edges down to prevent the poultice from drying too quickly.
• Allow the poultice to completely dry before removing the wrap. Proper drying time is 24 to 48 hours.
• Once the poultice is dry, remove the wrap and the poultice and rinse the area. Wipe dry with a clean, soft cloth.
• If the stain reappears, repeat the process. It may take a few applications for complete removal.
Once the stain is removed, the surrounding area may need to be cleaned to match the area where the stain was. This usually can be accomplished with mild soap and water, or with a stone cleaner available from your stone supplier. After stain removal and cleaning, ask your supplier for the name of a good-quality impregnating or penetrating stone sealer.
Includes information from McFarlane Stone Co., Bloomington, Minn.
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