There can arise a potential problem of slowly developing acid degradation on fabrics, especially fabric coverings to upholstery, but also draperies and textile wall coverings. This will slowly cause the fabric to appear darker or "burnt." The fabric and upholstery will become discolored to a tan, orange or brown color over time. The problem may be seen as irregular areas, streaks and blotches or an overall condition of discoloration with tan, yellow, orange or brown staining. This can happen when the fabric or furniture is treated with an acid or acidic finish.. During ordinary usage, the fabric is subsequently exposed to light, heat and moisture from sources such as sunlight, heat registers or radiators, and later wet cleaning. These conditions provide the environment that can contribute to acid type burns on cotton and cellulose fabrics..

The most common fibers and fabrics affected are those containing cellulosic fibers— namely cotton, rayon, flax or linen—and blends made from these fibers. One of the more common causes of acid burning is from applied finishes and acid salts used as fire and flame retardants (FR). These can often be found on natural fiber lining fabrics that cover cushions stuffed with goose down, feathers or cotton batting. Over time, the acid can migrate out to the face yarns and discolor the upholstery fabric. Customary wet extraction cleaning, the most widely used cleaning process, can inadvertently accentuate prior damage caused by acid burning.

Acid burning problems from fire and flame retardants have been occurring for more than ten years, although they are fairly rare. It appears to happen more so on higher quality, custom-made furniture and draperies. We believe the cause is the formation of oxycellulose and other tan-brown colored degradation products that can occur in cotton, rayon and other cellulosic fabrics. It can take several years for this discoloration to fully occur. But not all flame retarded upholstery linings, interliners, cushion covers or FR treated draperies will cause this problem. Certain FR treatments and fabric finishes are more acidic than others, contributing to the development of acid burn stains over time.

We do not know of any practical, definitive tests to foresee this problem prior to upholstery or drapery cleaning. Once these tan or brownish stains develop, they likely cannot, in our experience, be permanently eliminated. Oxidizing or reducing bleaches can temporarily improve the appearance by lightening some discoloration, but later (weeks or even months) the darker coloration or staining may return.