Why Did The Color Change?

October 25, 2019

Posted by D. A. Burns

Why Did The Color Change?

It’s become more common for companies to add dye to their product to make them more appealing, and we now see coffee, tea and wine being used to add color. The dyes can make the difference between a spot we can remove and a stain that permanently alters the color of a fiber. When a spill happens, there’s no surprise about the color change as you can see the added color right away. 


Sometimes a color change will occur and no one remembers a spill. The color in that area may have changed slowly over time and may have been hidden by every day soil. These spots of mystery can require some detective work to figure out, and there are inspectors that make their living trying to figure them out. There are “mystery spots” that we often encounter and can make a general guess about their origin. This is a list of the most common:

  • Stain Removers
  • Skin Care Products     
  • Particulates    
  • Insecticides
  • Fertilizers
  • Gases

Stain Removers

Products sold as spot/stain removers do more dye damage than any other mystery spot on our list. We see quite a number of textiles that have altered or missing color where a “spot removal” product did a great job of taking the color out of the spill while also slowly taking color out of the fiber.

The products most likely to do harm are the ones that contain bleach. Few people would use a chlorine laundry bleach to get spots out of their rug, but the ‘oxi’ in the name of many spotting products indicates it contains a bleach of a different kind. 

“Oxi” has become a bit of a buzz word in cleaning marketing, being used in the same way “turbo” is used to describe a performance car. Unfortunately, even some cleaning professionals buy into the hype and use products that contain peroxides, because the carpet looks so bright after cleaning. That brightness just might be due to a little color loss.

Oxidizers work to remove color by chemically changing the color source and “bleaching” the color away. This works well if the color in the unwanted spot is more easily changed than the dye in the textile. Due to the way they’re dyed, polyester, PET and some nylon carpet fibers can stand up to the milder oxidizers. Wool, silk, rayon, some nylon and any plant fiber like cotton will lose color if they come in contact with oxidizers. In addition, oxidizers can break down wool or silk fiber, often leaving a yellow-brown stain behind, as if the fiber has been burned.

The slow change is often due to the product being difficult to completely rinse from the carpet nap, so anytime humidity rises it continues to remove color.

One comment we’ve heard is:My (oxi-product) says it uses color safe bleach.”

There is no such thing as a color-safe bleach. Bleaches, by definition, remove color. Color-safe is often used as a marketing term for products that contain either an oxidizer or an optical brightener. Optical brighteners lighten stains by covering them with a light reflecting residue. Unfortunately, optical brighteners will slowly turn yellow, and the yellow is difficult or impossible to remove.

If you shine a UV-black light on a yellow spot, the spot may glow either yellow or purple/white. Yellow indicates a urine build-up. Purple/white indicates an optical brightener residue.

Skin Care Products

Number two on our list is skin care products, and the culprit in them is benzoyl peroxide. Yes, another oxidizer. Mostly known as an acne fighter, benzoyl peroxide is used in makeup, pet care products…even teeth whitener. The first part of what makes this mystery spot-producer different is that, being invisible, no one sees it rub off on textiles or fall onto carpet. It is difficult to completely wash from hands, so it can be easily transferred by contact. If some falls to the floor, it can be tracked to other areas.

The second part is that the damage to the fiber dye is done right away but doesn’t become apparent until moisture or warmth make the damage visible. (Heat and moisture are great chemical catalysts.) Typically, benzoyl peroxide damage can be identified by color loss and a residual pink or pale yellow stain surrounded by pink ring.


This is a collection of varied items that include anything that accumulate over time or requires moisture to activate: powdered bleach, copier toner, plant pollen, airborne soot. Get the carpet wet and the powdered bleach takes out color, the toner releases ink and the pollen releases yellow dye. These are spills that require careful vacuuming at the time of the spill to remove as much as possible before it gets packed into the yarn.

We once saw a carpet that had colored spots appear as it dried. Under magnification we found hundreds of tiny, colored particles embedded in the pile. The homeowner was an artist and sometimes liked to sit on the couch and use colored pencils to sketch out a new project. Each broken pencil point became a hidden color bomb.

Air borne soot can come from candles, cooking, car exhaust or other pollutants. These can move with the flow of air to go under walls, doors and draperies. Anywhere the air travels through carpet or fabric the particles are filtered from the air, and the textile slowly turns dark. Removal success depends on both the fiber and the amount of residue. Typically the only fix for “filtration soiling” near walls is to have a carpet installer pull up the edges of the carpet, caulk the base of the wall to stop the airflow and re-attach the carpet.


These are most often the culprit if a pink, peach or green discoloration appears in close proximity to baseboards. Pest control experts know insects will hide under baseboards, so need to spray there. The products they use are colorless at the time of application and can take so long to change the color of the carpet that the cause is forgotten. This doesn’t happen routinely, only when a particular pesticide combines with a particular dye. Best practice might be to have carpets cleaned after a pesticide application.

Fertilizers and Ice Melt Chemical

These can be tracked in from the lawn or sidewalk, and a little liquid fertilizer spilled while feeding indoor plants is fairly common. Fertilizers typically turn carpeting yellow to slightly green over time. A common pattern is a fan of discoloration at entrance doorways or multiple spots near indoor plants. Be careful when fertilizing houseplants, and if an application of ice melt or fertilizer is recent, outdoor shoes should be removed before walking on carpeting or rugs.


Called “fume fading” by carpet inspectors, this occurs when chemical fumes or pollutants in the air react with textile dyes. Fumes from laundry, pool and spa bleaches can remove color from the tips of carpet fibers. Naturally occurring outside ozone may also be a cause, and often color changing fumes come from ozone-producing air cleaners or from gas fired heating equipment. If the furnace is the cause, a color change will appear most vivid near heat vents. If you see this type of color change near vents it might be time for a furnace check.

Unfortunately, most of these color changes can’t be corrected by cleaning, and the cause of a lot of mystery stains will remain a mystery.

Hopefully, this information will help you keep your textiles safe from color changes, or at least your mystery spot won’t be so much of a mystery after all.


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