Altar bells are just as popular in their ritual use as an athame or wand, but may not get as much attention as those other tools. With an altar bell, they are meant to consecrate or to attune you to the gods or goddesses so that they can hear you in your prayers and ritual work. Therefor, altar bells are indeed an important ritual tool for your workings.
Before you begin any of your rituals or spells, you should go to your altar and ring an altar bell at least twice. The first ring, is to call out to your god/goddess and get their attention, with the second ring for “opening up” a link between you and them so that your god/goddess can channel their energies freely to you and empower you during your spells and rituals.
When not in used, you can keep your altar bells on your altar, and for cleansing them, simply light some sage and wave the smoke around the bell. The sage will cleanse the altar bell from any negative influences that may collect around it over time.
Altar bells come in all manner of shapes and sizes, as well as different materials, but the most common is brass because of the clear, high pitched tones that it creates. It is believed that altar bells with a higher tone work better because the higher the pitch, the more likely your gods/goddesses will hear your call with the altar bell. So although you can use any kind of bell you wish, many people prefer to have altar bells that reflect their faith, such as ones that have a pentagram, triple moon, or triquetra.
If you would like to shop for altar bells, or just to see various different kinds, you can do so here: