Cleansing: Carnelian is a fairly robust stone. You can cleanse it by fumigation using sage or palo santo, or briefly pass it under a stream of clear water. Avoid prolonged immersion if the stone is set in delicate metal.
Recharging: It particularly appreciates the energy of the sun (especially in the morning) to restore its radiance and vibrational power. For a gentler recharge, you can place it on a quartz cluster or an amethyst geode for a few hours.