Wicking the cause of a stain’s return

Soap, low-moisture method best way to get rid of unsightly areas on carpet

Q I have a problem with urine stains in my carpeting. I always clean them with my Bissell proheat 2X cleanshot cleaner as soon as I see them, and I always use Bissell products in the machine. After cleaning, the stain is gone — only to reappear later. I clean them multiple times but to no avail; they keep coming back. Is there something that I can do (short of taking up the carpeting) to make them disappear for good?

A There are basically two causes of reappearing carpet stains: residue from cleaners and wicking. Residue issues are most likely to show up where there is a lot of foot traffic when the soap used in carpet cleaners hasn’t been fully removed. This leaves the fibers sticky and prone to grabbing whatever dirt might be on shoes or pet feet. But when the reappearing stain is in a different place — for example, the carpet surrounding the leg of a chair, as in the picture you sent — wicking is the more likely cause.

Wicking occurs when urine or another stain saturates the carpet and sinks into the padding. Or an excess of cleaner could carry a stain into the padding. When you clean later, if the carpet fibers again become saturated, some of the moisture will reach the padding and re-liquify what remains of the old stain. The carpet cleaning machine will extract some of the liquid, leaving the carpet looking clean. But if the padding is damp, moisture laden with remnants of that deep stain will wick to the surface as the carpet fibers dry. And bingo! The stain will reappear.

Reappearing stains happen with professional cleaning, too. “Deep stains (such as pet urine or a spilled cup of coffee) are like an iceberg; often the visible stain is much smaller than what’s actually in the carpet backing,” Mytee, a company that makes floor-cleaning tools for professionals, notes in the “classroom” section of its website. “When cleaning carpets using an extractor, the cleaning solution used can re-wet those deep stains. Wicking then pulls up the residual staining agent from the bottom of the carpet fiber, causing it to reappear!”

Mytee recommends that professional carpet cleaners ask clients before the work begins if they know of any areas where stains reappear, or using a moisture meter to identify damp areas before cleaning begins.

It might seem counterintuitive, but the best approach in those areas is to clean lightly, so you clean the fibers of the carpet but don’t get any moisture into the carpet padding. Go over the area several times with a dry tool to get out as much moisture as you can. To ensure that any remaining moisture dries as quickly as possible, set up fans or switch on the air conditioner.

Mytee also recommends that pros consider using low-moisture cleaning techniques, such as an orbital cleaning machine — a type with a round base that can be outfitted for cleaning all types of floors. For cleaning carpets, the machine is used with a powdered cleaner that’s sprinkled on, worked into the fibers, then suctioned up. Because no liquid is involved, there is no risk of wicking up remnant stain from the carpet padding. You probably don’t want to buy another carpet cleaning machine, but you can try using a dry carpet cleaning product, such as Capture carpet and Rug Dry Cleaner ($9.99 for 16 ounces at Ace Hardware). The instructions say to first spray the area with Capture pre-mist carpet pretreatment & spot remover. You can order that from Amazon ($11.58 for a 24-ounce spray bottle), or as a kit that includes both products and a brush ($24.88). A representative for Capture said that many retailers now only sell the powder, which can be used on its own. Just sprinkle it on, work it in with a brush, wait 30 minutes and vacuum it up, she said.

You might try calling a few professional carpet cleaners. Explain your problem and ask whether they have faced this problem and are confident they can get rid of the stains permanently.

If none of this works, there is one more thing you can try short of replacing the carpet. Because you know you can get the stained areas looking clean, at least temporarily, call a company that does carpet repair to investigate whether it would be relatively easy to pull back the carpet and replace the padding that was saturated. Lou Selmani, owner of Sultan Flooring and Rugs in Silver Spring, Md., said that while it is possible to cut out a section of carpet, replace the pad and reinstall the carpet, the job is much better done by pulling up the carpet at the edge of the room, rather than cutting into it in the middle of a room. “I’d need to see it,” he said. Padding for an area up to 5-by-5-feet should cost no more than $50, he said.