Silk ties require a bit more care, given they’re made from delicate, fine fibers (they’re also incredibly smooth, which means your strands will gently glide against the hair tie without snagging). You may be able to get away with a longer time between washes, since the fabric is moisture-wicking, but they can still garner stains after some time.
When they’re ready for a clean, you can always machine wash on a cold, gentle cycle and hang them out to air-dry. Or you can use an extra gentle hand-washing method: Fill up a clean sink or bucket with cold water and a few drops of mild, unscented liquid soap. You can spot clean any stains beforehand by adding a drop of soap directly to the stain and using your fingers to gently rub it in. Then gently swish the silk tie in the sudsy water, letting it soak for 15 to 30 minutes.
Rinse the scrunchie in cold water a couple of times to get all of the soap out, then gently press it against the side of the sink or bucket to drain any excess water. Do not twist, squeeze, or wring it out (this can create folds and wrinkles in the delicate fabric), and let it hang dry on a rack or clean towel.