How to clean a Persian or oriental rug, and when not to

Vacuum a Persian rug gently in the direction of the pile, with suction only, and never run the vacuum over the fringe. Blot spills with cool water. Do not steam it or use a rental machine. A hand-knotted rug that is valuable, silk, very dirty or has dye bleeding needs a full specialist wash, not a home clean.

"Persian" gets used loosely for any rug with a traditional pattern. The advice below is for genuinely hand-knotted rugs, Persian or otherwise. If yours turns out to be machine-made, it is usually much less fussy, and the FAQ below shows how to tell.

How is a Persian rug built, and why does it matter?

A hand-knotted rug is a woven foundation with row after row of short tufts of yarn knotted around it, and the foundation is what decides how it reacts to water. Understanding that one fact explains almost every rule that follows.

Three parts matter:

• The pile. Usually wool, sometimes silk or a wool and silk mix. This is the surface you walk on, and the fibre chemistry behind it (heat, pH and dye) is covered in how to clean a wool rug, including the dye test. Do that test before any liquid goes on.
• The foundation. The warp threads run the length of the rug and the weft threads cross them. On most Persian rugs they are cotton. Cotton swells when wet, dries slowly, and browns if it stays damp.
• The fringe. On a hand-knotted rug the fringe is not trim. It is the ends of the warp threads, so it is part of the structure. Tear it and the end of the rug starts to unravel.

That construction is why a Persian rug is not cleaned like fitted carpet. Fitted carpet is usually nylon or polypropylene on a synthetic backing that shrugs off hot water. A rug with a wool face and a cotton foundation can shrink unevenly, brown along the fringe, or bleed one colour into the next if it is soaked and dried badly.

Silk is a separate case. Silk pile is weaker when wet, marks easily, and dyes on silk are often less stable. Rugs sold as "art silk" or "bamboo silk" are usually viscose, which is fragile in a different way, and the area rug cleaning page explains that one plainly.

What can you safely do at home?

At home you can vacuum, rotate, deal with fresh spills and keep the fringe tidy. Everything beyond that carries more risk than it is worth on a good rug.

Vacuum, gently. Consumer Reports' guide to caring for antique and area rugs warns that the rotating brush on an upright vacuum is too harsh for oriental rugs and recommends a canister or a suction-only setting. It also says to vacuum in the direction the pile is meant to lie. Run your hand along the rug: one way feels smooth, that is the direction.

Keep the vacuum off the fringe. Vacuum up to it, not over it. A brush roll or a strong nozzle will catch the fringe, wrap it and tear it. Comb it straight with your fingers instead.

Do the back now and then. Turning the rug and vacuuming the back shakes out the grit that works down into the base of the knots, where it grinds at the pile.

Rotate it. Turning the rug end for end now and then evens out traffic wear and sun fading.

For a fresh spill:

1. Lift anything solid with a spoon or the edge of a card.
2. Blot with a dry white cloth, pressing down, from the outside of the spill in. Do not rub, which spreads it and roughens the pile.
3. Dab with a cloth dampened, not wet, in cool water.
4. Blot dry again, then put a folded dry towel under the spot with a weight on top for a while.
5. Raise that part of the rug and run a fan across it so it dries from both sides.

Do not:

• Use a steam cleaner, a rental carpet machine or hot water.
• Use bleach, ammonia, oxygen powders or general carpet shampoo.
• Soak the rug in a bathtub or hose it down on the driveway.
• Bleach the fringe white.
• Hang a wet rug, which can distort it under its own weight.

Consumer Reports also suggests a professional clean every one to three years, depending on household traffic, and the same article quotes advice to follow the rug maker's own cleaning instructions where there are any.