Probably more people are induced to change their carpet due to unsightly red stains, than those who do so because the carpet is badly worn. This is especially true where there is light colored carpet. In many instances, a homeowner will just try to cover the ugly red stains with an area throw rug instead of having the carpet cleaned. This is sometimes an acceptable or tolerable solution, but perhaps not the best possible one.
Many red stains are difficult to remove. Some may have become permanently fixed and therefore impossible to eliminate, but in most cases, if we understand the source and nature of the problem, we can get rid of the stain.
Red stains are either synthetic or organic. Synthetic stains are usually formed by the color additive FD&C Red #40 which is an azo dye approved by the FDA for use in foods, drugs and cosmetics. Drink manufacturers use it extensively to color various drink mixes especially Kool-Aid, but it is also to be found in numerous other types of food, medicines (like cough syrup), furniture stains, and cosmetics. Organic stains are those derived from naturally occurring substances and products like blood, jams, jellies, tomato and other fruit juices, and condiments.
The first question to be asked before tackling a red stain problem is: What is the source of the stain? If you know the answer to that question, the task becomes much simpler. In any case, when the stain is fresh, time is of the essence. Blot up as much of the spill as you can, immediately. A clean white cotton towel is preferable, but paper towels will do. Be careful not to rub the stain sideways as this may cause it to spread. If you have a wet vac, flood the area with water and then suck up all the moisture you can. This procedure will be most helpful where the stain is derived from natural substances that are soluble in an aqueous stain removal agent.
Stains caused by synthetic dyes are much more difficult to remove without affecting the coloring agents used to dye the carpet fibers initially. In order to achieve this it is usually necessary to apply a combination of chemical solutions to the carpet fibers, and apply heated water vapor to get the dye in solution and transfer it to an absorbent material like a cotton or paper towel. A clothes iron with the setting at moderate heat is usually used for this. Great care must be used, or the color could be bleached out of the carpet fibers, thereby presenting another, and probably much worse problem.
Perhaps the best solution is to call in a professional cleaner who is familiar with the properties of industrial chemicals, and who has sophisticated equipment to deal with this type of problem.