Carpet Cleaners have seen a substantial increase in complaints about spots and discoloured areas of freshly cleaned carpets. Most are the result of reactions to the increasing number of chemical products used in the home. We feel that you can deal with these complaints more effectively if information is available to enable you to ask the right questions. We are not addressing common stains where the carpet is stained or discoloured by foreign materials but rather those where the dye is either destroyed or changed. The chemicals known to cause problems are detailed below in groups.
ACNE MEDICATIONS In the past few years dozens of products have entered the market containing benzoyl peroxide as an active ingredient. This chemical is a very strong oxidising agent capable of destroying most dyestuffs used in carpet. Products containing it have been responsible for complaints of mysterious yellow stains, which appear where apparently no spill has taken place. These stains begin as orange to yellow as the dye is bleached and progress to lighter yellow as the oxidation proceeds, on blue carpet they may appear slightly pink. In most cases they exhibit an orange ring or halo which moves outward as the spot grows. Other textiles such as pillowcases, sheets, towels, upholstery fabrics and clothing may also be affected.
INSECTICIDES There have been several products entering the market for do-it-yourself flea and tick control. Testing indicates that some of these products can cause colour change by chemically changing the dye from one colour to another, ie, a red dye in a beige carpet is converted to blue, giving the carpet a green cast. Recent research indicates that Diazinon, Vaponite (DDVP) and Malathion, can cause the problem
FURNITURE POLISHES Several furniture polishes have been shown to cause a catalytic action, sensitising the dyes to sunlight. Red dyes have usually been destroyed, causing green or blush discolouration.
PLANT FOODS Spills of liquid foods or leakage from flowerpots have caused oxidation spots. These typically develop near the backing and process upward to the surface, with the actual spot not being apparent for months. These are usually dull yellow in colour.
URINE These spots also begin at the backing and progress upward over a period of time. They may be dull yellow or even red. The characteristic ammonia-like odour will be present for only a few hours but it replaced by a musty colour. The hydrochloric acid in both human and animal vomit has been known to cause spots even if cleaned up very well.
BLEACHES Chlorine bleach (sodium hypochlorite) is used in almost every home an may be eventually spilled. Note that many of the plastic jugs leak a little around the cap and drips occur as the bleach is carried into the house. "All fabric" type bleaches (oxygen bleach_ can also cause bleaching and dye bleeding but are slow acting.
Most mildew killers contain bleach and will affect textiles if used indoors.
ACIDS Some Toilet Bowl Cleaners contain as much as 9% hydrochloric acid along with some colouring agent. The acid can dissolve the nylon while the colouring matter stains. There are some dyes, which turn bright red when contacted by these products. Tile Grout Cleaners contain 5% phosphoric acid. Corn and Callous Removers contain 14% Salicylic acid plus 9% glacial acetic acid.
STRONG ALKALIS Drain Cleaners contain Sodium Hydroxide (lye), Sodum Hypochlorite (bleach) and do a good bleaching job. Oven Cleaners are gelled Sodium Hydroxide.
WHAT CAN CARPET CLEANERS DO!
What can be done about these spots? Generally, nothing; the dye is either destroyed or changed chemically and can't be restored by cleaning or treatments. Carpet manufacturers can't prevent them since there are few known dyes which are resistant to such cmeical attack, nor cover them under warranties since they are certainly not defects in the carpet. Remember that all carpet manufacturing processes are batch or continuous in nature and that all areas of the carpet are treated the same; other than rare dye spots (always darker, never lighter, than the background), these complaints are always the result of a foreign substance of some sort.
The above information represents the best available knowledge at this time. Since lab testing has been done under one set of conditions, other conditions might yield totally different results. This information is offered for your guidance on evaluating complaints and answering consumer questions.