Recurring Carpet Spots

Why Spots Come Back

We occasionally have clients that want to replace a carpet because they have spots that keep coming back. They clean the spot, and it is gone. Then a few weeks later, the spot is back. The good news is: You don’t need to replace the carpet if you know what causes recurring spots.

There are three main causes of recurring spots.

Sticky Spots

Something that attracts dirt got on the carpet. This causes over 97% of recurring spots. A partial list of substances that attract dirt are: sugar, oil, detergent, grease, adhesive residue (such as after removing tape), soft drinks, urine, ice melt, and butter.

Many people who have these spots don’t believe they caused the spots to begin with. The dribble of soda that got on the carpet didn’t cause a stain at that time, for instance. But the sugar in the soda creates a sticky residue that attracts dirt like crazy. Over a period of time, as people walk over that area, dirt sticks to that spot more than any other area on the carpet. It happens gradually, until you have a dark, dirty spot on the carpet. The stickiness is not necessarily obvious to the touch, but it can be.

Here’s an example that will make this easier to understand. If you’ve ever removed duct tape from something (a desk, for instance), you noticed that your desk was sticky where you removed the tape. Shortly thereafter, that part of your desk is dirty. That’s what’s happening to your carpet.

Coffee Stained Carpet. A coffee stain. If the coffee has sugar, we might clean the stain, but have a spot come back later.

So what happens when you clean the spot? Since the sticky residue is just sticky enough to attract dirt, but not so sticky that your foot gets stuck on the carpet (usually), it’s often not a big deal to clean the dirt off the surface of the carpet. However, if you don’t remove what attracts the dirt, within days or weeks, the spot reappears.

Many consumer cleaners are detergent based. Detergent is great at removing the initial layer of dirt, but then we have a problem. Detergent is one of the items that attracts dirt. If we did not remove the detergent from the carpet, we are making the problem worse, not better. Most consumer cleaners work by adding detergent to carpet, without providing any means or instruction to remove the detergent. The spot comes back. As we use more detergent, the spot grows.

There is nothing wrong with the carpet. But there is something wrong with the cleaning method. It is essential that we not only remove the dirt, but we also remove what is causing the dirt to be attracted to the spot. It is also important that we don’t add more “stuff” to the carpet that will attract dirt (like detergent, without removing it).

As a general purpose carpet cleaner, we recommend Capture brand cleaner. It is a dry cleaning powder that cleans without leaving detergent residue. Capture is effective for a wide variety of spots and stains. Use the powder generously, and leave it on the carpet for longer than the directions indicate. The directions say to leave it for 30 minutes. We recommend using it overnight. It is non-toxic, so it is safe to use with children and pets.


Wicking occurs when a liquid staining agent appears at the bottom of a yarn, and the liquid ascends the yarn through capillary action. Wicking requires that the base of the carpet is wet. Wicking does not happen with dry carpet.

Here is the specific scenario where wicking causes a recurring spot. Purple grape juice is spilled on the carpet. A professional cleaner uses a cleaning wand to inject detergent solution into the carpet to clean the spot. When the cleaner no longer sees the spot, he stops, neglecting that there is still purple stain at the base of the yarn. The cleaner also fails to extract the excess moisture (and detergent) from the yarn.

Later, and usually within 24 hours of the cleaning, we notice that the purple color has migrated back to the surface.

Since grape juice also contains sugars, how do we know that we are experiencing wicking and not a “sticky spot”? We know by the color and the length of time for the spot to reappear. If the sugars in grape juice are attracting dirt, we will have a spot that is dirt colored (black, gray, or dark brown – or whatever the color of dirt is in your area). If we are experiencing wicking, the area will be purple. The length of time for the spot to recur is also a clue. If the spot recurs within 24 hours of wet cleaning, it could be wicking. But if the spot recurs after a week or two (or even a month or two), then we have a sticky spot, not wicking. Again, wicking does not happen with dry carpet.

We can also tell the difference by touch. You can often feel the dirt caused by a sticky spot. But a stain (which is different than a spot), does not feel different than the rest of the carpet.

Wicking does not happen only with brightly colored staining agents. Wicking can also occur with . . . dirty water. Again, how do we know the difference between wicking and a “sticky spot”. Color for one. Wicking dirty water will give the carpet an overall dull grayness, as opposed to the more intense black/gray/brown of a sticky spot.


Mold is the least common recurring spot, and the easiest to recognize. Mold is always a moisture problem. Always. You need to have a wet carpet to grow mold. Mold usually has a distinctive odor. Because of its rarity and ease of identification, I will not discuss this particular issue further.


Common Misconception 1: The spots must be coming from underneath.

Actually, gravity works the other way. It is much more likely that something is dropped from the above. Sticky spots are most common. The reason so many people believe that something is coming from underneath is they are not seeing the spots being made. Several days later when the spot begins to appear, they have long forgotten the little splash of sugared tea they got on the carpet, that didn’t immediately show a stain on their medium colored carpet. Kids drip Popsicle juice, causing little dark spots many days later. Again, because it takes a period of time for the spot to show up, we forget what originally caused it.

We have had client’s insist that they are not causing the spots and the spots must be coming from underneath. But then an inspection of the yarn reveals that the dirt is just on the top of the yarn, and the base of the yarn is clean. How could it “come from underneath” if the base of the yarn is perfectly clean? Answer: It doesn’t.

Common Misconception 2: I’ll save money by hiring the cheapest professional carpet cleaner I can find.

No. No, you will not. The cheapest carpet cleaner will have inferior (cheaper) equipment. The cleaner will not be adequately trained (it’s an easy business for amateurs to enter). And, the cleaner will not rinse and/or extract the detergent thoroughly. Detergent attracts dirt. The cheapest cleaner is going to leave all that detergent in your carpet. The carpet will look clean when the cleaner leaves, but it will quickly resoil. You saved $40 or $80 on the cleaning, but you are instead replacing what would have been perfectly good carpeting years before you should be. Cheap carpet cleaners can cost you thousands of dollars in premature carpet replacement. Select your carpet cleaner by reputation, not price.

Hopefully, this will help everyone with the issue of recurring spots, so you can get years more enjoyment from your carpet.