What happens if you wash viscose?

Is this rug worth cleaning? If it’s wall-to-wall, hire a professional in-home carpet cleaner. But for wool, silk, cotton, Navajo, Turkish, Afghani, Berber, Chinese or other woven rugs, the answer can often be found on the blog Rug Chick. Lisa Wagner, Rug Chick herself, is an owner with her mother of K. Blatchford’s Rug Cleaning in San Diego. Ms. Wagner teaches rug cleaning to professionals; her next workshop, in McKeesport, Pa., is April 24 through 26. “I share our mistakes over the decades, ” she said. Ms. Wagner was born into the business; her father, Don Blatchford — her parents are long divorced — is a rug broker. Her mother, Kate Blatchford, is a weaver and rug-repair specialist. Ms. Wagner is, in other words, a rug geek. “I’m part of a Facebook group, ” she said, “that posts pictures daily asking, ‘What’s my rug and where’s it’s from?’ ”

Q. Oriental-style rugs are sold everywhere. How do you know it’s a good rug?

A. If you can see the same design on the back as on the front, that’s woven. Buy that, not tufted. Wool is the best; practically indestructible and sustainable. Hand-woven is the most valuable. It’s a piece of the weaver’s soul. But Karastan does very good machine-woven rugs. On the other hand, if you see a canvas or burlap material on the back, that’s a tufted rug. Those are typically made in India and China, where they use a lot of glue and sometimes bad latex. It looks like a pile rug but may last only 5 or 10 years. Woven wool rugs last centuries.

Q. I’ve heard of artificial or “art silk.” What does that mean?

A. I had a decorator come in with a rug and say, “It’s a wool and silk rug.” I had to say, “It’s a wool and viscose rug.” It was labeled “manmade silk.” You’d think that means silkworm silk, not machine-made viscose. Viscose rayon is weak. It yellows, doesn’t hold colors. It sheds. If you buy a room-size silk rug, and it’s under $1, 000, it may not be real silk.

Q. Can you vacuum too much?

A. Today’s vacuums may be too aggressive, especially if there is hard floor underneath. You need to sweep a wool rug with a carpet sweeper. When you vacuum, once a week or two, use a canister vacuum, and set the beater bar high for less abrasion. Vacuum from side to side, not end-to-end, so you don’t grab the fringe. Once a year, take the rug outside and vacuum the back to get embedded dirt out that causes fiber wear. Then vacuum the top again. If you whack a corner and see a dust poof, it needs to be washed.

Q. You say rugs should be washed every two to three years. Why?

A. Even if a rug doesn’t look dirty, it slowly gets duller and the fringe starts to look bad. If you wait, dust, especially silica, sinks down. Whether the base is cotton or wool, when it’s walked on, those pieces saw away at the fiber. That’s what makes a rug go bare, not foot traffic. It’s foot traffic on a rug that hasn’t been swept, beaten and washed — even if it has a good rubber rug pad underneath, which cushions compression.

Q. What are common mistakes?

A. Putting a plant on a rug. Years later, you take the rug up, and a perfect circle drops out. The pad doesn’t allow air to circulate. A wool rug may feel dry, but moisture has seeped to the bottom. First mildew, then dry rot, and you have to repair.

Q. Do you handle all kinds of rugs?

A. Yes. Navajo rugs are similar to Afghani rugs in that they can bleed when they get wet. In preparing the wool for weaving, there needs to be a lot of rinsing. In Afghanistan and in the desert there is limited water, so the weavers start with wool that has extra dye.

Q. What makes you frustrated?

A. It sometimes costs less to make a rug abroad than to clean it here. We charge about $4.50 a square foot. People bring in a rug with a latex backing. It’s shedding powder. The marble dust to stiffen the latex, that’s the white dust you see under some rugs. I say skip cleaning, because it costs more to wash and repair such rugs, and apply the savings toward a good woven rug.