In modern Wicca, however, the cauldron is still regularly used. It can be placed in a sacred or ritual circle and used to burn items during a ritual, to hold the ingredients necessary for aspell or incantation, for scrying in water, as a container for making brews and potions, or to provide a vessel in which transmutation, germination and transformations may occur. It is a symbol of the womb of the Goddess, and of rebirth, as it was in ancient British Celtic religion, and is therefore sacred to the Goddess.
In some traditions of Wicca which incorporate aspects of Celtic mythology, the cauldron is associated with the goddess Cerridwen. Celtic legend also tells of a cauldron used by warring armies, in which dead warriors could be placed and returned to life, although lacking the power of speech (and possibly lacking souls, like golem). These warriors could go back into battle until they were killed again. Also, in Irish mythology, Tir-Na-Nog, the Irish Land of the Dead or Otherworld, was presided over by a crone and her cauldron, to which all life returns to await rebirth.
Courtesy of http://www.witchcraftandwitches.com/terms_cauldron.html
Cerridwen gathered herbs when they were the most potent and magically charged by using water and proper energies from the Sun, Moon, and stars. For a year in a day in a cauldron her potion needed to be stirred while nine witches breathed life into her desire and keep the fires burning. A blind man and his aid Gwion Bach would assist with the stirring. Cerridwen knew the time drew near when three drops of brew would jump out of the cauldron onto her son and her spell would come true.
Morfran was placed close to the cauldron for the final stages. Cerridwen exhausted instructed either the blind man or his aid to come and wake in the forest before daybreak so she could witness the transformation.
All was quiet in the castle as the blind man and Morfran slept while his aid attended the fire. For almost a year and a day the aid, Gwion listened to the chants and began to want the gift that was being offered to another. He decided to take Morfran's place. As the brew began to bubble fiercely, Gwion pushed Morfran side to allow the three drops to spring onto him. The mixture boiled over with wailing shriek, cracking the caldron, and spilling the potion into the flame. Cerridwen awoke. Gwion Bach, now transformed, could see her rage because her wish for her son had been destroyed. Gwion turned himself into hare and begun running through the corridors of the palace. Morfran's mother, shaped as a hound, nipped at his heels. Gwion fled outside the castle and through the long grass. Glancing behind, he saw the white of her fangs. Gwion reached the shore of the island and changed his shape into a fish and swam through the reeds. When he glance behind again, he saw an otter on his tail. Shooting to the surface, he shape-shifted into a swift (bird) and soared across the sky. Behind him, with fire blazing in her eyes and talons ready, Cerridwen had changed form into an eagle prepared to kill. Gwion dropped toward earth. He spied a wheat field and turned himself into grain. With razor sharp eyes, Cerridwen saw what he'd become and shaped herself into a hen who hunted and pecked until she devoured all Gwion had been.
Cerridwen returned to her castle satisfied justice was served, only to realize she was pregnant with the seed of Gwion. For nine months she thought of ways to rid herself of the seed growing inside, vowing to destroy that which she bore. on Beltane, she took the young Gwion to the waters and cast him where he drifted, leaving him to his fate.
At the sea's edge near Castle Degney, in north of Wales, a lord's son identified as Elphin was fishing for salmon. While moving through the reeds he came upon the child. He looked at the boy and quickly named him, "Beyond the Radiant Brow." The infant replied, "Taliesin, it is."
Lord Elphin was not a wise man, squandered his money but his heart was pure. He and his wife raised the Taliesin who became loved by the Celts. The people of the land were amazed by his knowledge of words. He understood that they were the foundation of every spell and charm.
The Welsh wizard Taliesin songs were about creation and transformation, and they made those magical things occur.
With the power,
knots, images, and charms,
the witches focus is heightened,
charms to protect,
some against the unwanted,
some hold healing.