See it connected with the four elements which are symbolized by the objects on your table. Imagine that the impurities are drawn away for the talisman to be. Finally, take the talisman, hold it in your hand, and strongly blow on it, imagining that all impurities are blown out of it into their respective elements. Blow first, connecting with the fire element. Next connect with the air element, then with water, and finally with earth.
Similar procedures apply to crystals and gemstones.
Those may also be put into salt water for a day or so. Salt is a universal cleanser that absorbs impurities. Therefore, you may also use salt for metal and for paper or parchment. In this latter case salt is recommended, of course, and not salt water. When working with salt, be sure to imagine that the impurities will be absorbed.