One of the major characteristics of rayon, also called viscose, centers around the care of the fabric. For those of you who have been around rayon a lot, you know that there are both washable and "dry clean only" rayons in the garments that you sell. Why are there both washable and non-washable rayons? Originally rayon was a "dry clean only" fiber. However, the fiber producers discovered that they could create washability in rayon by putting certain finishes on the surface of the fabric after it was knitted or woven. But this also added to the price. So, today many rayons in the marketplace remain untreated, and are therefore "dry clean only."
It's very important to read the labels, and make the customer aware that just because he or she may have purchased a washable rayon last week, that doesn't mean that all rayons are washable. Anytime a rayon garment, labeled "dry clean only," is washed, a risk is taken, and one of three things may happen. First the garment can shrink tremendously, sometimes as much as two or three sizes. Second, the garment may fade, or a printed pattern may bleed. And third, the fabric may lose its soft hand. The rayon that was once soft and drapeable may become stiff and harsh.
There´s also something important to remember when caring for the washable rayons. Most of the washable rayon garments today are labeled "hand wash, cool water, drip dry or dry flat." And, it's important that these directions are followed, because when rayon is wet, it actually loses 30% to 50% of its strength. So, hand washing, like the label says, is the best. The constant agitation of the washer, and tumbling of the dryer will beat the garment against the side of the washer and dryer. And, eventually this causes the fiber to break down, and shorten the life of the rayon garment. So, in order to get the maximum life out of your washable rayon garment, it's best to hand wash and drip/hang dry.