Caring for silk rugs can be a more difficult and time-consuming job than rugs made of synthetic fiber or wool because silk, itself, is a protein that resembles human hair, and is more readily damaged than other rug fibers. Since almost all silk rugs are handmade rugs, they also need individual hand cleaning to preserve their quality. Preventing initial damage to the rug is the first step in its proper care.
Silk rugs should be placed in low-traffic areas and out of direct sunlight, which, over time, can fade the dyes in the rug. If a rug is in an area that receives significant foot traffic, it should be rotated 180 degrees periodically to maintain even levels of wear to its surface. Ultraviolet light in sunlight is also a common reason for colors to fade, yet most modern windows filter out this type of light naturally, and older window panes can be coated with a light filtering film available at hardware stores.
Before dealing with a stain, spill, or animal urine, it is important to determine if the rug is pure silk or a combination of silk and wool. A silk-and-wool combination rug will show more durability and resistance to stains, and water will bead up on a rug with wool content, since it is water-resistant. A definitive test is to remove a small section of loose thread from the back of the rug and burn it. Silk will have a distinctive hair-like smell when burning and ball up into a pile of ash, whereas other fibers can smell like paper or plastic and melt as they burn.
The first step in removing stains should be to determine the degree of color fastness of the dyes in the rug by applying a small amount of water-based detergent to an area of the rug and then rinsing it out to see if any color bleeds out with the detergent. If the rug rinses clear, the stain should be blotted with a clean cloth soaked in club soda or a 50/50 mixture of vinegar and water. The rug should then be rinsed thoroughly with water to remove all chemical traces, and air dried by hanging.
Cleaning ordinary dirt from silk rugs should never be done through dry cleaning or steam cleaning, as both processes will leave gritty residue in the rug and cause the colors to fade. Vacuuming with a non-brush and non-rotating hand attachment is recommended, or gently shaking the rug in the air to detach surface dirt. Any abrasive cleaning of the surface will result in damage to the silk fibers.
Antique silk rugs, especially Persian rugs such as Indian silk rugs and expensive Chinese silk rugs, often have vegetable-based dyes used as their coloring agents, and these tend to be delicate. Moth damage can also be present in antique silk rugs, as any portion of it in darkness, such as parts under furniture, will attract moths. The best moth preventative for long-term protection of silk rugs is the use of zinc fluorosilicate, commonly sold as a moth-proofing agent.
The best method for cleaning and caring for a silk rug then is to try to avoid wear to it in the first place, to keep it out of direct sunlight, and to gently clean up spills immediately. Before resorting to any chemical treatment of a spill, rinse the rug area thoroughly in water. Rugs that appear very resistant to stains or damage may in fact be fake silk rugs made out of mercerized cotton. Professional chemical tests can be done to definitively determine a rug's nature, and what care is necessary to preserve its value and beauty.