However they are used on a couple of types of magick--which are different than knot magick.
Some Wiccans use cords can be used to consecrate tools and other items. After anointing the item with oil, and putting whatever markings on it, she or he removes the cord form her/his waist. S/he then wraps the cords around the item to be consecrated, while saying:
"Cord go round,
Power be bound,
Light revealed,
Now be sealed."
S/he visualizes the powers as a white or blue white light passing as a white light from the cords directly into the item.
S/he then binds the spell by tracing a pentagram over the item
Another form of cord magick can be used when coveners participate in a group magick. One method involves coveners looping their cords together holding the cords taught as they sit in small ring to one side of the altar. Coveners chant something suitable to raise energy, either EKO EKO, the Wiccan Chant, or some other chant or appropriate word or phrase to focus the intent. When the cone of power peaks, whoever is directing the cone signals everyone to drop the cords. Coveners release the power, breath deeply, and allow the residue to go to ground back into the earth.
The second form of group magick involving cords, except is more like the ring dance. As they stand in small ring on one side of the altar, coveners loop their cords together holding the cords taught again forming something like a web or spokes of a wheel. Coveners walk around spinning the wheel while still holding their cords taught--as in the Ring Dance circling clockwise, deosil, sunwise. Eventually chanting faster and gaining momentum. At culmination of this spell, whoever is directing the magick signals everyone to drop one end of her/his looped cords releasing the magick and sending off the cone of power as each covener draws her/his cords out of the web or wheel. (Interestingly this form of cord magick bears a striking resemblance to an Italian spell recorded in an 19th century paper on Neapolitan witchcraft. See Dancing Healing Magic)