It is always wise and advised to cleanse it before you perform any form of divination. The easiest and simplest way to cleanse your pendulum would be to take some incense or a sage smudge stick and light them to where they are smoking well. Take your pendulum and pass it through the smoke several times. You can perform a prayer as you pass the pendulum through the smoke for added benefit if you choose. Another way for cleansing would be to make up a salt water bath for it. If your pendulum is made from a gemstone that is not harmed by water, this is a good method for cleansing. Take some cold water and mix it with some salt, preferably purification salts, though dead sea salt can also be used. Dunk your pendulum into the water several times and then when finished, dry it off very well. For metal, wood or certain stone pendulums (such as selenite) this is not a good method as the salt water can damage your pendulum, so the sage smoke cleansing method would be better suited for these pendulums.
Before you use a pendulum it is always best to ensure that you perform a protection ritual or spell beforehand. The reasons for this is because when using any form of divination tools such as crystal balls, scrying mirrors, or pendulums, you are opening doorways not only to your subconscious, but also to the spirit world. Spirits often are summoned through divination whether intentionally or unintentionally to aid the seeker in finding their answers. I recommend a white light of protection spell.
1. Personalize your pendulum mat. I have provided 4 Amazing Pendulum Boards for you to use if you do not have one. 2. Personalize your ritual by inscribing symbols or adding herbs, oils or candles to your workspace and/or pendulum. 3. Hold the pendulum in your dominant hand. Let the cord or chain run through your fingers so you hold 2-3 inches of chain in your hand. Let the pendulum dangle over your pendulum card, and make sure the tip of the pendulum is in the center of the cross. Also make sure you are not gripping the chain too tightly, just enough to keep it steady. 4. Focus on the question you want the answer to. It must be a yes/no question. Ask the question aloud. Make sure the only thoughts in your head are related to the question you have. 5. Keep your hand as still as you can. As the pendulum begins to swing back and forth slightly, keep your hand still. The pendulum will start doing it's job by swinging back and forth in line with the answer it is providing.